Yes, you can /assist <name> but your assist target needs to be in-combat for it to work. By in combat I mean actually fighting/shooting a target.

For healing I typically use group-heals (Doctor) or you can use the F1-F6 keys. I forget exactly my old setup but the way I would invite the group would always keep the leader as F2 on all the alts making /following easier.

I experimented with 1 enforcer, 4 NT's for AOE'n and Doc for group heals and it worked very well as clumsy as it was. If you have the gear 5 soldiers and a doc it would an easier situation to manage.