Issues with AI traffic incursions, what the PF3 conflict monitor can do and cannot do as well as the downsides of the use of the conflict monitor have been discussed here several times now.
I think creating an algorithm that covers all the different airport layouts and all conceivable traffic situations is virtually impossible.
A solution would be if the user himself could easily freeze the AI traffic around him temporarily if he realizes a situation where a conflict might evolve. And the user most often will be able to do so better than any computer-algorithm (that's why we still have human air traffic controllers on the tower...).
Since PF3 principally is able to freeze AI traffic (as the conflict monitor proves) I imagine it shouldn't be too hard to implement a hotkey to manually freeze all AI ground traffic within a certain radius (maybe 2 nm to cover a full runway length). No complex computations on which aircraft to freeze and which not. Just freeze everything until the hotkey is pressed again. Maybe add a timeout-function (1 minute?) in case the user forgot to cancel the freeze.
Regards
Ralf