how do i pair one magic mouse and keyboard per computer in a room with 28 imacs?

I am a graphic design lecturer and we just upgraded our computer lab from pc to mac. I am struggling to pair 28 magic mice and 28 bluetooth keyboards to 28 different machines in my classroom. Is there a way to do this without them interfering with one another every time they are switched on? Such as pairing each machine with a default mouse and keyboard so that it doesn't detect the others?