Simple answer - Rock
Lots of rock. Look a my DIY journal and you'll see a mix of males, some singles and nothing with the 1m 3-5f ratio. I lost 2 Socolofi o inter species agression but have 6 Haps in there, 5 Synos and 2 breeding pairs of Afra and Labs, lots of attitude but too many caves, tunnels and crevices to defend. Not peaceful but no hassled fish what so ever.
I firmly believe with enough rockwork you can eliminate detrimental aggression unless you have something daft like 3m and 1f. All male tanks have been known to work with mbuna but it depends on individuals my Hongis are the quietest fish in my tank.
afra and labs are really peaceful species and wont normally hassle them to death. syno's are catfish and arent relevant either.
rockwork may help, but not in the long run, you will just get the already weaker fish being out competed for caves and the fighting will continue. sightlines or not. follow the advice already stated, get rid of some males and add alot more females.
did you not read up about cichlids before purchasing them? its a crime if you didnt.