How do you add custom NPCs to a spawner?

I’ve searched high and low but I can’t figure it out, I’m using the spawn platforms and I really want to add some custom NPCs like the Mobile Infantry SNPCs from Dan’s Mega SNPC pack so I can group them into squads and not have to constantly spawn more. I’ve found that Dan’s pack has individual spawn points for each NPC, but nothing that can put them into a squad (as far as I know)

Sorry if this has been asked or if it’s in the wrong place, but seriously I’ve looked and I can’t find the answer.

I know this thread is old. But I too have been searching for this answer for a long time now. I have been using NPC Spawn Platforms which has some standard NPC’s in it:

It would be great if someone could answer this question, or even point me to the right place. I have tried several keywords without success.