Oh geez, you've got a handful!!!
I would definitely try separating them. Sounds like they're ganging together and feeding off each other, so to speak.
I'd also try sending 1 to your Mum's house, or daycare or somewhere, while you spend one-on-one time with one of your twins by themselves. Coffee date with mum, etc. I know that will be so difficult with 3 kids to try and get 1 by themselves - but maybe they just need that individual time with you?
I would think that they're not bratty kids, but maybe more acting out to get your attention. If they think its funny when you get mad at them, then I would assume they just want to see you yell and scream, rather than crying and getting scared when you hit the roof.