Thanks. After poking around in blender, I found my answer, But I appreciate the info. I did not know that about studioMDL!

I've been working with fairly simple models with few bone layers, so I decided to try my hand at more complicated models.
I came across a model that was rigged using Auto Rig Pro tools, and the model contains multiple armatures via bone layers (Bendy bones, twists, etc.).

My issue is: whenever I export the model into Source Filmmaker, source tools chooses to export the hidden armature full of the bendy bones only, instead of the ones that are visible on the viewport.

My questions is: Is there a way to influence which armature, or rather preferred parts of the armature with the preferred bones, are exported through source tools? If you can as well, explain why this happens?

Thank you for any contribution!