The behavior you are describing is completely normal. Gross, but normal. Just keep in mind that even the most docile, laid back females can transform into Class A Bi***es when they are in heat--so can the females around them. Even if they all love each other and get along at other times, some of them (not just the female in heat) can become territorial and aggressive when in heat. I would advise supervising them as closely as possible when they are together and separating them when you can't keep an eye on them.
(Thus the reason why I have 3 dogs in 3 separate rooms of my house right now when I'm not there
)