Welcome to the forum.
The 3D solids in your model appear to be AEC objects, right?
Too bad, because if they were regular 3D solids you could use the INTERFERE command
and INTERFERENCE CHECKING to trim everything up.
I just figured out that you did this with the cylinder tool from the MODELING toolbar.
If you redo them, in place over the ones that are already done, using the PRESSPULL command
you could pretty easily recreate this with regular 3D SOLID objects which would give you the earlier options mentioned.
I don't know anything about LITIO, but this could be done in Autocad too.