Is it possible to link maps on a map on bnet?

just what my title says: Is it possible to link maps on a map on bnet?

if you mean like in the orc campaign,... no

No. P1 player goes from map 1-2, P2 goes from map 1-2, but p2 wont see p1 because it will serversplit.

The only way is to save the characters with a code (numbers/letters) and require them to load their characters on the next map.