I have a mesh that has a internal geometry but not like vertices inside of a closed geometry but rather the faces that are not visible from the outside let me explain with an image:

as you can see the red area indicates the faces on the "inside" how would i go about removing these?
I want to remove the internals to reduce the vertex count! since i wont ever see them anyway.

If my question is unclear or needs extra info let me know so i can clarify!