While simply binding similar spells to the same keys can work to an extent, it's going to be very inefficient in the end. For mixed teams you'll usually want some way of creating "rotations" for your characters to go through. Most commonly people use either an addon called Gnomesequencer (I'm fairly certain there will be a classic version) or the ISBoxer pro configuration. Some people also combine parts of both, which is fine as well. All very much dependant on how you choose to run your team.