Function which handles the spawning of a dynamic group of characters. The composition of the group can be passed to the function.
Alternatively, a number can be passed and the function will spawn that amount of characters with a random type.
Note
Before Arma 3 a side's Center must have been created before a group may be spawned either by using createCenter or an editor placed (0% Probability of Presence is fine) unit of the appropriate side.
When using this function for making a dynamic AI spawn, pay attention to the fact that none of the created groups will be marked for auto-deletion when the group become empty (all members dead). It means that it can be very easy to hit the 144 (288 for A3) max groups per side limitation, implying that no more AI or group can be created afterwards. To avoid this issue on Arma 3, don't forget to use deleteGroupWhenEmpty command in your script.