We can't just give them non-functioning abilities so they're easier to arrange, that'd be essentially like giving every faction repeats of the same unit to fill the build bar. If you want to suggest an ability for a unit, feel free to use
this thread. But really there aren't even enough abilities in the game to allow us to make each one its own group. You could always just double click on the unit you want and that automatically selects all of the units of that type.