Dynamically select assigned users on Workflow Board

I love the new Workflow board and actually like the Assigned To swim lanes (i.e. who the responsible PO is for each Master Feature), but having to manually assign users is a pain.  The entire company is in one giant Aha workspace meaning thousands of users.  I cannot simply select all users, so I have to manually select users within our area.  Unfortunately that changes more often than I'd like.  If I don't catch it and add them, then features disappear from the graph.  I'm always wondering if I'm actually seeing everything.  Then I see a lot of empty swim lanes since I've added everyone that MIGHT have something assigned to them.  This needs to be fix.  I should be able to configure it so that it automatically selects all the users that currently have something assigned to them and not show those that don't.