Does Fluent support two differnt fluid domains in a simulation?
 

Is it possible in a Fluent simulation to have two different fluid material domains separated by a solid material domain so that the solid material can act for Conjugate Heat Transfer?

I am expecting similar feature to what CFX has- Unchecking Constant Domain Physics

Yes. You just need to setup different "cell zones" and then you'll be able to apply different material properties to each cell zone.