On master
/invite [toon 1]
/invite [toon 2]
...

On slaves
/target party 1
/focus target
/targetlasttarget

And bind it on the same button. Jamba auto-accepts party invites... good to go...

I use the Z key to manually set a target for my slaves, if i want to switch tanking targets i can do it freely. Also, if i press the dps macro button and don't have a target that can be hit i want to select my focus'es target.

My dps macro is something along the lines of

/target [noexists,noharm] focustarget
/castsequence reset=combat ..... <dps macro >
/script UIErrorsFrame:Clear()

This way i can put the dps on a target and just go with a toon and pull more mobs to the dps, switching targets when the first one is dead..