You can program in multiple moto sites control freqs into one bank providing that there is little chance of actually being able to receive/scan both sites at the same time. So if one set of control freqs are 100 miles away from the other, no problemo but if the scanner can receive both sites at the same time your scanner will become confused. And this confusion will make your scanner start smoking then fall to little pieces onto the ground.
Oops, I mean it will get confused and stop scanning the systems altotgether.