I'm sure this has happened to many and lately has become a nuisance. Whenever a great group of people are entering in an interior, at the same time, the majority get stuck, and it takes a pretty good amounts of pressing shift for jumps to start seeing popping out of this great conglomerate of stuck people in the marker.
This mostly has been happening in Bankrobs, criminals all rush to the interior as soon as possible to group inside. So my suggestion would be to take away collisions from markers, at least from bank interior markers. It would go a long way to improve the fluidity of these events.
Of course, I'm not aware of the implications this could have, so if someone who's into the dev'ing part may shed a light, shed the light!