Most african cichlids in the 'assorted africans' tank are mbuna and for the most part are compatible with each other to a degree.
In some instances, however, you may find non-mbuna in the assorted tanks, such as nimbochromis venustus (the 'giraffe cichlids'), usually very small ones. These probably do better in hap set ups, rather than mbuna set ups as they require high protein diets, aren't as territorial, and get fairly large (10"+). I wouldn't consider them very compatible with mbuna.