Linking wormholes
When a signature is a wormhole, it can be linked to the connection it represents on the map. This ties the in-game signature ID to that connection, so the whole group knows exactly which hole in space leads where.
How a signature gets linked
Linking is deliberate, not automatic — pasting a scan won't guess which hole goes where. A signature is tied to a connection when you record the jump through it: as you map as you fly, you pick the signature you jumped through, and that signature is attached to the new connection.
If a signature stops being a wormhole (for example a re-paste reclassifies it), its connection link is cleared automatically.
A connection takes one signature per side: the signature is the hole, so two of them on the same side would be two scans of one hole. Pointing a second signature at a connection that another already holds therefore hands it over, and the first goes back to being an unlinked scan, free to take the hole it really is. That is what you want when two holes in a system lead to the same place: they are two connections, each with its own signature, mass and lifetime.