I'm trying to figure out how to simulate a system that simulates a liquid and a gas. Actually there are two liquids and a gas. I recently posted about two different liquids. I've solved that problem. The two materials mix and then exit into the atmosphere the air determine how the materials exit and in what shape the pattern is in. Think airless paint gun.

After selecting the three materials the in the setup I am unable to specify the air with out making in the default material. However, then I'm only able to select the air and cant get the liquid into play.