whoa! my bad, the group name is a global variable, so you would only have the name of the group of the last person to spawn there.
maybe something like:
activation:counter = counter + 1;call format ["group%1",counter] = group this
then everytime a unit spawns they will have their own group name, i think.
group1
group2
etc
you would need to give counter a value of zero in init so that will work