Multifasciatus are a fun species tank to keep and an excellent introduction to Tanganyikans.

Try to gather a few bits of slate-work for some escape-hole-caves and lots and lots of escargot shells. You need a minimum of one shell per fish (I'd recommend at least two or three per fish, personally). When scaping the tank - don't be too precious about the sand as they will move a lot of it around in their quest to build their kingdom...aka partially bury their prized shell - you just need to concentrate on creating a set-up with lots of broken lines of sight. This is important for stress limiting and will keep bullying to a minimum. Also - either overstock or not at all. Anywhere in-between will just create upsetting bullying...fairly typical of both Tang and Malawi cichlids! You could probably keep six in a 20gal long.

Look up jeffs99dime on this forum. He has a very nice little species tank which may be just what you're looking to create.