Multi-floor support?

[SinusPi]

How do I get Carbonite to show and properly support waypoints placed on specific floors of specific maps?
Or to even SHOW submaps like caves and sewers..?

Suppose I'm plotting a path towards the Blackrock Depths entrance. I have to go through Burning Steppes, then Burning Steppes floor 14, then it'll switch to being Searing Gorge 14, into Searing Gorge 16 where the dungeon portal lies.

Normally, I'd just
Nx.Map:GetMap(1):SetTargetXY(Nx.AIdToId[29],21,38,"Blackrock entry",false)
... but then, I'd like to put floor 14 in there.

Is it in any way supported, or (due to the 230-ish maps limit, or something) am I out of luck?