I have always given the advice to put one pair in a small tank (10-20 liters) if you want to breed licorice gouramies. But there are many people who don’t think of breeding, only of keeping nice aquariums with a group of those fish, and then you will get this problem.
To solve it you can only separate the pairs. In the present setting success of only one of them is not sure. The gallon jar could be a temporary solution.
There are only two perfect possible solutions: Either, you concentrate on one good pair and give the others away. Or you set up more tanks. Breeding tanks should be small (see above). I have no technical devices in them, even no filter. But then you must use good growing swimming Ceratopteris, java moss and the like. And you must be prepared to change water regularly every week. Two or three small tanks of this kind equal less than one big tank. And you could compare different pairs in their breeding success.