More smoke domains in one scene

Im gonna make a movie with alot of smoke and fire in it. but if i put 2 smoke somains too close to eachother one of the fire/smokes messes up when i try to simulate them, the closer there are the earlier in the simulation they fuck up.

I cant use the same domain for both since they have different settings.

Is there anything i can do or is it just how blender is?

Also another questiong: If i want the smoke to go up i set the temperature to above +1, and if i wnat it to go down i set it lower than -1. But what is i want it to go sideways?

Physics stuff only interact when they are on the same layer, so put each domain and its emitters/obstacles/force fields and such on a different layer and you should be good.

Temp diff is one of many things that can cause smoke to rise and fall, and it only works vertically. You can adjust emission settings or add a force field if you want smoke to go sideways. Use the wind field if you just want a constant push in a particular direction. If you want it to spray away from the emitter, increase the normal-speed attribute on the emitting object.