Pipeline, what I am asking is much, much simpler.
A single track for VST sound module, that would be independent from other parts of BIAB mixer.

P.S. some months ago I did request a feature of lanes, similar to what you described, but that will unlikely to happen, but adding a single midi bus channel will add many independent midi tracks that can be fully controlled from VST interface, yet be a part of whole mix in BIAB.