I have a set of meshes I know will be in front of another set, how can I make sure they are processed first for best occlusion?
I also have a third set that I don’t wish to be affected, thankyou.
Maybe I am using renderingGroups incorrectly.
Maybe I just don’t have to worry about it or I should run a local pass.
You should not worry to much about that but if you do you can enable front to back sorting on your meshes to render the closers first and then let the depth buffer optimize things for you
Depending on how complex are your meshes you can also use depth-prepass:
https://doc.babylonjs.com/how_to/optimizing_your_scene#using-depth-pre-pass
Anyhow, you need to test and measure 
Depth pre-pass is the term I woke with on my tongue.
That setting for sure doesn’t flatter my fps, I think I can probably just trust bjs internals to take care of it. thanks @dk!
always my pleasure!