A shared segment is a set f bridge port and of mac addresses. 

The shared segment belong to a broadcast domain and has an upper port

the so called designated port.

The bridgebridgelink holds all the bridgeport. And the relation is by using the designated port as a common port.

The bridgemaclink holds information about the macs on shared segment. And for each mac and for each port is saved a row. A shared segment with 20 mac addresses and 3 ports has on 2 entries in bridgbridgelink and 60 entries in bridgemaclink. 

The best way is to use the designated port to indentify the shared segment also in the bridgemaclink so that instead of saving 20 mac address for each bridgeport we save the 20 mac address for the designated bridge port.

A migration tool for moving from the old perspective to the new is needed.