in addition to the setview(), I find having a kgpanel or similar area on the slaves (just offset from the center of the screen). Then I have a mouse repeating region setup, when I click there (or press meta-iwt key), all the slaves have that area right clicked.

So in Dal when I want to send all the toons through a portal, i just need to click that box on the main and all the slaves do so as well, same with mage portals, warlock summons, same with 'use' quest stuff and what not.

Some glitches with it of course, I have the area on the master up my the minimap versus in the prime center area to avoid accidental mouse move events. but practicing with just the portals in dal and being able to 'dismount, meta-iwt key' and poof I am in the next city makes it all pretty easy.

This is how I mass looted with slaves before iwt as well, so maybe I am tuned in for positioning them.