My 3 female cats keep going into heat back to back.?

What's going on. I mean after one is in for about a week then another then again and again and again!! Then all of them start all over. It's continuous. They are about I year old not fixed and have started peeing on everything even though they used the litter box before and it's changed every other day. I have a male (their brother) that is fixed. What is their problem? Will White vinegar in a rug doctor take the odor and stain out of my carpet and couch? PLEASE Help ...I want to clean today as I have been out of town and I came home to a pissy house and cat's STILL IN EAT!@! Will geting them fixed stop the peeing and heat problem??