There are various party macros, guess I must be misunderstanding exactly what you are looking for.

A macro such as this will leave your current party:
/script LeaveParty()

Or have the leader use this on every slot:
/uninvite PlayerName

You can then do this for every slot:
/invite PlayerName

More than 5? do:
/script ConvertToRaid();

I am not sure if it can be done from within the addon but also see no reason why it should have to.

I am guessing you are doing it for the same reason I do. I put all 10 of my toons in a raid so I can fly there using dual-mounts, then once there I split into 5-man groups so they get credit for the quests.