You are essentially using a target based assist.

This would function identically to "The No Focus Manifesto".
Where each toon targets others in a fixed order, based on who is present and alive.
And then your spells are:

/cast [target=targettarget] Nuke



This works great in that Focus is free for whatever.
And is not dependent on a party leader, so will work in pvp as well.

I'd forum search for No Focus Manifesto.