Changing particle data dynamically?

Hi all,

I tried to look this up in the forums but I can't find a thread that covers it (or I can't get access to the promising looking threads in the search results). I have a building that I want to emit different kinds of smoke at different times (brown, black, white). I have the 3 ParticleData smoke datablocks defined and 1 ParticleEmitterData datablock which starts out using the white smoke (as the "particles" field in the datablock). Is there a way I can switch to the other ParticleData objects on the fly? If so, how do I do this? If not, I guess I can make 3 different emitters and switch between them, but I was trying to avoid that if possible.

Thanks!

Edit: or I guess just being to change the particle color dynamically would be fine too. :-) But I don't know how to do that either.