Would it be possible to add a mission selection menu (via config file or better would be a ingame menu) where the player could select what mission he would like to start right now (robbery, suicide, etc...)? Or are you already planning something like that?
Normally I like patroling and waiting for random callout, but sometimes I just want to play a short round or a specific mission and then it's hard to wait for the right mission - and even then after waiting, you never know - it could be a prank call!