Thanks for all the replies. The jist of it is that maybe you can, and maybe you can't. 
I only intend to use something like this once, not as a regular tactic, as it is indeed expensive. But the Queen of Chaos and her general Miska are coming up, and the DM did use mordenkainen's disjunction on us, so I figure I've got the right to at least one underhanded tactic.
I'll check with my DM first, of course. I don't want to ruin the encounter for everyone.
Andargor

I only intend to use something like this once, not as a regular tactic, as it is indeed expensive. But the Queen of Chaos and her general Miska are coming up, and the DM did use mordenkainen's disjunction on us, so I figure I've got the right to at least one underhanded tactic.

I'll check with my DM first, of course. I don't want to ruin the encounter for everyone.
Andargor