It works. But my understanding is that one strain will eventually out compete the other. Part of the fun, I think, is toying with the timing, for instance, starting with one and then adding another more attenuative strain to finish things up. Actually, I'm thinking about making a wheat wine today that I'll first pitch on a CA ale cake, shooting for clean flavors, and then let a Franco-Belgian strain finish things off to get to a super-dry finish.