So how about {nelmoH}? {A DanelmoH} might mean "you cause A to match,"
but match what? {A B je DanelmoH} might mean "you cause A and B to
match," but that doesn't mean A and B are matching each other -- it
means you cause A and B to match something else -- but what?
The problem is that {nel} takes a subject and an object (the two things
that match each other), but not a third thing. And you can't use the
prefix trick with {nelmoH} because there is no non-third-person indirect
object.
So to give the command "Make A match B," you have to do it periphrastically.
I'm a little late on this, but what about -vaD? We've seen it used before for sentences where -moH is used on transitive verbs and the original subject gets relegated to a -vaD noun, in the form of B verb A -> AvaD B verbmoH X. Would that not work here? DochvetlhvaD Dochvam DanelmoH "You make this thing match to that thing", or "You make this thing a match intended for that thing" (to translate -vaD a little more literally).