Dont do it. The fish dont know how to react to the others aggression which causes stress. Stick with 1 continent and you will find much more success and happiness in your tank.
I thought the same thing once, They are all cichlids, they will be fine and can fend for themselves. WRONG.
There are certain cases where Africans can work in SA tanks, but I wouldnt suggest anybody under 5-10 years of fishkeeping to try it. It usually leads to chewed up fins on your SA fish and dead africans.
Plus a saum, JD, and Tex fill up a 125. Thats already too much aggression for that tank.