diff --git a/sandy/core/endf6.py b/sandy/core/endf6.py
index 434741c5..e21a249b 100644
--- a/sandy/core/endf6.py
+++ b/sandy/core/endf6.py
@@ -1871,7 +1871,13 @@ def get_errorr(self,
         12 /
         1.00000e-05 3.00000e-02 5.80000e-02 1.40000e-01 2.80000e-01 3.50000e-01 6.25000e-01 4.00000e+00 4.80520e+01 5.53000e+03 8.21000e+05 2.23100e+06 1.00000e+07 /
         3/
+        3 452 'nu' /
+        3 455 'nu' /
+        3 456 'nu' /
         3 251 'mubar' /
+        3 252 'xi' /
+        3 253 'gamma' /
+        3 259 '1_v' /
         5/
         5 18 'chi' /
         0/
@@ -2317,7 +2323,13 @@ def get_gendf(self,
         12 /
         1.00000e-05 3.00000e-02 5.80000e-02 1.40000e-01 2.80000e-01 3.50000e-01 6.25000e-01 4.00000e+00 4.80520e+01 5.53000e+03 8.21000e+05 2.23100e+06 1.00000e+07 /
         3/
+        3 452 'nu' /
+        3 455 'nu' /
+        3 456 'nu' /
         3 251 'mubar' /
+        3 252 'xi' /
+        3 253 'gamma' /
+        3 259 '1_v' /
         5/
         5 18 'chi' /
         0/
diff --git a/sandy/njoy.py b/sandy/njoy.py
index e21ea0a4..477cb3cc 100644
--- a/sandy/njoy.py
+++ b/sandy/njoy.py
@@ -81,6 +81,7 @@
 import pdb
 import tempfile
 import subprocess as sp
+import pytest
 
 import pandas as pd
 import numpy as np
@@ -186,6 +187,7 @@
 NJOY_TEMPERATURES = [293.6]
 NJOY_SIG0 = [1e10]
 NJOY_THERMR_EMAX = 10
+banned_xs = [251, 252, 253, 259, 452, 455, 459]
 
 
 def get_njoy():
@@ -791,7 +793,7 @@ def _groupr_input(endfin, pendfin, gendfout, mat,
                   iwt_groupr=2, lord=0, sigz=[1e+10],
                   temp=NJOY_TEMPERATURES[0],
                   spectrum_groupr=None, mt=None,
-                  iprint=False, nubar=False, mubar=False, chi=False,
+                  iprint=False, nubar=False, mubar=False, chi=False, xs=True,
                   nuclide_production=False,
                   **kwargs):
     """
@@ -807,8 +809,6 @@ def _groupr_input(endfin, pendfin, gendfout, mat,
         tape number for output PENDF file
     mat : `int`
         MAT number
-    chi : `bool`, optional
-        Process chi (default is `False`)
     ek_groupr : iterable, optional
         derived cross section energy bounds (default is None)
     ep : iterable, optional
@@ -830,6 +830,10 @@ def _groupr_input(endfin, pendfin, gendfout, mat,
     mt: `int` or iterable of `int`, optional
         run groupr only for the selected MT numbers
         (default is `None`, i.e., process all MT)
+    chi : `bool`, optional
+        Process chi (default is `False`)
+    xs : `bool`, optional
+        Process multigroup cross sections (default is `True`)
     mubar : `bool`, optional
         Proccess mubar (default is `False`)
     nubar : `bool`, optional
@@ -848,6 +852,12 @@ def _groupr_input(endfin, pendfin, gendfout, mat,
     `str`
         groupr input text
 
+    Raises
+    ------
+    `SyntaxError`
+        if xs=True and the selected mt is not appropriate, i.e. if it
+        corresponds to nubar or mubar information
+
     Examples
     --------
     Default test without keyword arguments
@@ -951,27 +961,28 @@ def _groupr_input(endfin, pendfin, gendfout, mat,
     0/
 
     Test mubar:
-    >>> print(sandy.njoy._groupr_input(20, 21, 22, 9237, mubar=True))
+    >>> print(sandy.njoy._groupr_input(20, 21, 22, 9237, mubar=True, xs=False))
     groupr
     20 21 0 22 /
     9237 2 0 2 0 1 1 0 /
     'sandy runs groupr' /
     293.6/
     10000000000.0/
-    3/
     3 251 'mubar' /
+    3 252 'xi' /
+    3 253 'gamma' /
+    3 259 '1_v' /
     0/
     0/
 
     Test chi:
-    >>> print(sandy.njoy._groupr_input(20, 21, 22, 9237, chi=True))
+    >>> print(sandy.njoy._groupr_input(20, 21, 22, 9237, chi=True, xs=False))
     groupr
     20 21 0 22 /
     9237 2 0 2 0 1 1 0 /
     'sandy runs groupr' /
     293.6/
     10000000000.0/
-    3/
     5/
     5 18 'chi' /
     0/
@@ -1013,7 +1024,10 @@ def _groupr_input(endfin, pendfin, gendfout, mat,
     10000000000.0/
     3 2 /
     0/
-    0/       
+    0/   
+
+    Test the wrong mt number:
+    >>> with pytest.raises(SyntaxError): sandy.njoy._groupr_input(20, 21, 0, 22, 9237, mt=[102, 455])
     """
     iwt_ = 1 if spectrum_groupr is not None else iwt_groupr
     ign_ = 1 if ek_groupr is not None else ign_groupr
@@ -1042,14 +1056,26 @@ def _groupr_input(endfin, pendfin, gendfout, mat,
                                           spectrum_groupr[1::2]))
         text += [tab1]
         text += ["/"]
-    if mt is None:
-        text += ["3/"]  # by default process all cross sections (MF=3)
-    else:
-        mtlist = [mt] if isinstance(mt, int) else mt
-        for mt_ in mtlist:
-            text += [f"3 {mt_:d} /"]
+    if xs:
+        if mt is None:
+            text += ["3/"]  # by default process all cross sections (MF=3)
+        else:
+            mtlist = [mt] if isinstance(mt, int) else mt
+            for xs_ban in banned_xs:
+                if xs_ban in mtlist:
+                    raise SyntaxError("Introduced mt is not appropriate for xs")
+            else:
+                for mt_ in mtlist:
+                    text += [f"3 {mt_:d} /"]
+    if nubar:
+        text += ["3 452 'nu' /"]
+        text += ["3 455 'nu' /"]
+        text += ["3 456 'nu' /"]
     if mubar:
         text += ["3 251 'mubar' /"]
+        text += ["3 252 'xi' /"]
+        text += ["3 253 'gamma' /"]
+        text += ["3 259 '1_v' /"]
     if chi:
         text += ["5/"]
         text += ["5 18 'chi' /"]