I don't know why buy I find a hearty handshake between two women to be very awkward.
Why are you thinking about women being close and in close proximity of each other?
I think it's awkward to shake a hand with someone you are less intimate with. And I'm not saying that they should not do it but it's just my opinion.
You are within your right to not have physical contact with others, but I do not think that it is right of you to think that others can't do otherwise nor is it awkward for them to do so. I feel that you need help in trying to feel less awkward with physical contact, so I suggest you get a therapist addressing this very issue.