Who Pays For The Bridal Shower?

I am a briads maid throwing a Jack & Jill shower for my friend. Her sister(Matron of Honor) sent an email asking all wedding party members(guys and girls) to contribute to the party, a portion of which will also go towards a gift. One of the brides maids sent an email saying that because she could not attend the shower, she did not feel responsible to pay for it. She also said that, as a briads maid in other weddings, she has never been asked to "throw" the shower. What do we do? Also, there are other wedding party members that live out of state and can not attend. Does this exempt them from paying for the party as well? Help!