Levitate-the-party Macro

[Fogyreef]

<dredge> Water walking, too.

Though that brings up the next step. Levitate is Priest specific. What if I wanted to grant water walking to the party?

I'd like to have a click bar button called Water Walking that worked generically, i.e. with any team comp, as long as there was a Priest (Levitate), Shaman (Water Walking), DK(Path of Frost), etc. in the party.

Ideally, in cases where I have two or more water walk-granting toons in a group only one of them would cast to keep things elegant. Using something like Aragent's "!if (character in "Death Knights Blood") /cast Path of Frost" method, is there a way, once a water walk-granting toon buffs the party, that the macro could exit before other water walk-granting classes get the request?