[gmx-users] How to create a group for a set of atoms with make_ndx

[sunyeping]

Dear everyone,

I am trying to select a set of atoms and create a gropu for this atom set with make_ndx. 
My protein has two identical identical chains, with each containing 110 residues.  I need to select residues61-101 in chain A and residues 69-94 in chain B as a group.
 The atom indexes for 61-101 in chain A are 816-1467, and the those for residues 69-94 in chain B are 2563-1964.
 I don't know what is the correct syntax for the atom selection. Could you help me with that?

Best regards.