Asset custom snap points - possible, or just for tracks/road?

I posted this on the Steam forums, but I get the feeling technical questions might be better suited on here

I'm trying to build a sort of track-planning asset, which doesn't collide with or alter the map/tracks/etc...
But I'd really like to be able to define its own snap-points, ideally with tangents for orientation snapping, so that I can snap one to another to allow building a chain of them easily. The way that you can define "snapNodes" for "TRACK" and "STREET" edgeLists, but ideally so it had its own custom type and only snapped to itself.

Anyone know if that's remotely plausible? Or are snap nodes strictly hardcoded to track/road edgeLists?

Nuts. So I take it there's no way to create a new "type" of edgeList? It'd be okay using them provided I could keep it from colliding-with/snapping-to other edge types.