Haplochromis species are generally longer and not quite as high in the body as Aulonocara species. Some Haplochromis cihclids are brown or greys whereas Aulonocaras (peacock cichlids from Lake Malawi) are usually blues or blue with red or yellow for the males, and females are silver. Female Haplochromis are usually the same colour as the males but not always.
Most good pet shops will keep different species and different colour forms of Aulonocara in separate tanks so they don't mix up the females. And they try to keep most of the other cichlids in single species tanks unless they are running low on tanks.
If you post pictures of them we can tell you which are Aulonocara species.