If they can't read the data in the other product, then they can't add it.
Otherwise, have to detect location and revise programmatically after
submission to remove from affected or spin off a derived CN isolating said
products. I could see that two furniture components being completely
unrelated, but having a similar team member handle same approval/rejection
being an issue here. In lieu of altering the UI, the detection algorithm is
best. Altering UI might include utilizing a different data utility or form
processor to search for affected, but then this doesn't get around OOTB
searching, so best to detect and remove undesired but affected from the
object itself, optionally revising the CN and setting older rev of CN to an
appropriate state with record of cause.
Hope that helps.