Hello, and welcome to the frog forum first off. African clawed frogs can mate about 3-4
times a year. There is really no way to control it except to separate them, sorry. However, most won't hatch and you can sell them to local pet stores, give some to friends, or sell them here in the Sales/Trade section. That or you can just get rid of the eggs, but without the proper care, the eggs wont hatch and the the tadpoles wont mature into frogs.