[gmx-users] a problem using g_sgangle

[Za Pour]

Dear gmx users
I am trying to analyze the results of my simulations. a system
including one CNT+12 small molecules.I would like to know the distribution
of angles formed by  these 12 small molecules around CNT.I have found from manual that 
g_sgangle may do that however, in the manual has been said that groups in this program
 are defined by a number of atoms given in an index file and may be two or three atoms in
size. but my small molecule has 60 atoms.would you please tell me is there any way I can
solve the problem.
thanks in advance