The second parameter is an array of groups, so you can pass any number of groups in one call - so no you don't need to call it for every member or even every group! Just call it once and pass every group that you want to respawn (in the second param).
An example call:
[hPlayer,[groupA,groupB,groupC,groupD],12,"SuchRrifle",0.5,100] exec *scriptname*
This would keep four groups at 12 guys each, with Russian Rifleman from Digital Grenades Marine Assault Pack, with a skill of 0.5, creating replacements within 100 meters of the guy hPlayer.
Every five seconds it would create as many new Russian Riflemen as needed to keep all 4 groups at 12 men each, and send them moving towards wherever hPlayer is located. You can include as many group as necessary in the second parameter.