I like dumb questions!! Cos at least "I" can answer those!! Hehe!!
I'm not quiet sure how You exactly want it but here is an idea!
In the russian group's waypoint, the one where they are holding the area, in the "On Activation" field, type:
CounterAttack = True
Now put a waypoint for Your M-60 straight in front of him (almost over him) and in the "Condition" field type:
CounterAttack
Then add to Your M-60 a second waypoint where You want him to counter attack.
That should work!