Because my show tanks are community tanks and because I will often house breeding pairs of some shell dwelling species in these tanks, it's inevitable that some of the pairs will successfully breed. If I'm intent on raising fry, I will keep breeding cichlids in their own tank. Otherwise, I just let nature take its course, while being cognizant of aggression.
Something to keep in mind with this approach is that keeping breeding pairs in a community tank will invite breeding aggression - between the pair and conspecifics, and between the pair and any trespassers/predators. Therefore if you choose to go this route and keep your breeding pair in the community, you should take a few steps to minimize the aggression. Such as, you ask?
Let's start with conspecifics. Mitigating aggression in this case is highly dependent on the gender and number of conspecifics. Males of many species simply won't tolerate another male in the tank, especially if there is a female present and a pair has formed. Unless you're knowledgeable about the breeding behaviors of the shellies you keep, you're best bet is to simply don't keep more than the pair of a given species in the community. It's not worth the risk. Your best bet is to start your breeding with the pair in their own tank.
The trespasser/predator problem is a bit simpler to address. You already know that most cichlids are territorial. Turf defense often becomes more acute when eggs and fry are involved. To minimize aggression toward trespassers and to offer your potential fry a fighting chance (assuming you want the fry to survive to maturity and you don't take the "let nature take it's course" approach), make the defense of the space easier. There are many ways to do this but the easiest is to employ some simple military strategy - use the natural surroundings to bolster the defense. In the case of an aquarium, use the glass.
A breeding pair of shell dwellers that have set up camp in the center of a 90g aquarium have to defend from all sides plus from above. I like to use the corners of the tank so the glass protects from two sides. I simply move the shells to the corner. This potentially accomplishes several objectives - reduces the stress of the pair, reduces their protection efforts, confines the space for the fry, and maximizes space for the other fish to avoid the pair.
There are other strategies, but following these will make fish keeping more enjoyable for you and the fish.
The Cichlid Room Companion
Tropical Fish Hobbyist
American Cichlid Assoc.
African Cichlid Hub