How do I stop the growth of an invasive houseplant?

Hi! I have an Alligator plant (mother of millions/thousands, flea cactus, mexican hat plant). I have had one before, and it grew to be many many plants. I was wondering how to keep the plants down. When I bought her, (I named them Alice and Allie J tee hee hee) Alice had a baby with her, and she was sprouting seeds, and I think a couple seeds fell. How do I keep the growth down to ONLY Alice and Allie J?