Can you share what tricks you've taught them? I quickly taught my cat that when I pat the ground, that I want her to come over.
However, she doesn't always come...She knows though. She usually comes over.
I did it to show her that things like her 7 pet blankets are hers, so I patted them and she came running over since she seemed to understand then that that means it's okay. I pat the top of my bed and she understands that that means I want her to jump up and join me. She doesn't always though...but she knows.
I am debating toilet training her one day...but that's a while away.
EDIT: Oh, I misread your post! I read too quickly and thought you said your cats do tricks.