They were within a few city blocks of each other for one session, because another player unwittingly traveled through a portal to our campaign finale from two years ago, when the party was at Castle Waterdeep stopping a coup attempt while Blackstaff was at the docks fighting off a group of raiders and their ships.

They didn't realize at the time that their future selves were there at the docks helping out Blackstaff while Mhair Szeltune used her magic to re-stabilize the portal so they could get back to their own time.

It was fun!