Interior Face Problem
 

Hello everyone. I'm meshing fuel cell with ICEM.There are solid-fluid-fluid-fluid-fluid-fluid-fluid-solid bodies from top to bottom.There are two problems at the faces between the fluid bodies.First of all,after meshing the faces which I mentioned before are become wall instead of interior. Secondly and the most problematic issue,after meshing ICEM splits interior surfaces randomly.For example, one of the face between the fluid parts splits three or four surfaces however it should be only one surface.How can I overcome my problems?