c_ignore (var group1, ..., 0)
Sets a list of entity groups to be ignored on the following c_rotate, c_trace, c_scan, or c_move call. An arbitrary number of groups between 1 and 30 can be given; the last number must be 0. A7.85
group1 - first group to ignore (1..30).
..., 0 - more groups, followed by a 0.
// look if an entity not belonging to groups 1,3, and 5 can be shot at, and if yes, trigger its EVENT_SHOOT event
c_rotate, c_trace, c_scan, c_move, group, collision