How about using 1 switch as the mode switch? Use a toggle switch to select how the other 2 switches act.

Mode switch = 1, other two act as switches 1 & 2. Mode switch = 0, other two act as switches 3 & 4.

Or use a normally open mode switch. Press once, in mode 1. Press again, in mode 2.

Kind of like the Shift key on your keyboard that doesn't need to be held down to select other key functions.