Annoying Roommate! Help!?

Okay so I live in a dorm, its basically a suite with 3 other girls. 4, including me. One of my suitemates is extremely annoying. Never have I ever met anyone who talked so much in my life and someone so over dramatic. I knew her freshman year and she would literally through tantrums on the floor of my dorm screaming like a mad woman at the crack of dawn whenever her bf and her would get into a fight. So with that said, I wasn't too happy when I found out I would be living with her this year. Not much has changed, she is extremely loud and will talk your head off whenever she sees you. I guess I wouldn't mind so much but everything she says is about other people that I dont know, she just gossips for the heck of it. I try to keep it short and sweet with her and sometimes I dont say anything to give her signs that I dont care. But it always fails, she will still keep talking. It's bothering my other suitemates as well that now they wont speak to her when they see her outside of our suite. She came to me today and asked if there was a problem with one of them because apparently she didnt speak to her when she saw her last night. I dont know how to politely say its because you're annoying. I hinted at it a little bit and said sometimes people just dont always feel like talking and she still didnt get it and was like "well that's not a reason to be rude." I just need some advice on how to politely tell her that she is annoying everyone in the house because she doesn't seem to get it even with the signs we are are giving. Any advice?