plant four varietals of the same fruit in a clump.
This might be preferable to a 'Fruit Salad Tree' [© by an Ozzie co.]for general health & maintenance, but prob'ly requires careful consideration of planting distances for noninterference- pruning could be tricky if they're too close, roots intertwining, etc.- but that could be addressed thru good nursery advice. Our friends in Rosamond have had good luck with a multi-peach, with different bearing times, but I think it was a multi-cherry they gave up on after 2 attempts. I think their multi-apple is ok. You must be in a less-stressful climate area than the high desert, and without apples shouldn't need cold-weather setting [except for cherry? Dunno].
Maybe search Ag Extension online for pertinent infos?