Not lesbians, chicki -- bisexual women. Heck, they can even be straight (that'd be good enough for me! ). Having it with a girl and another guy wouldn't be as fun because I would only be able to engage with one person vs. two if they were both women. Of course, for women who entertain the idea of a threesome, they would probably prefer it to be with 2 men.
And why do they have to be college or college-aged girls, waw? I thought women hit their sexual peak around 30 or in their early 30s. I would think that women in this age range would be more likely to be game than the younger girls.