How do I tell our group of friends that I am no longer friends with my 2 best friends?

Last yr, my best friend married. Small wedding, 2 bridesmaids & 2 groomsmen. I was Matron of Honor & our other best friend was Maid of Honor (Md of H). At rehearsal, I was igned to stand next to the bride. In privacy, I asked the bride if she was OK w/ the placements of her friends. To make sure it was how she wanted it. She said yes. (My husband is the Groom's best man & stood next to the groom). The Md of H got jealous & the next day just hrs B4 the wedding the bride told me that the Md of H was upset that she was not standing next to her. The bride asked me to step down from my position. I was extremely upset, but carried on with all my duties w/ a smile. The Md of H never spoke to me again. I waited 2 mos. after the wedding to let the bride know I was upset. Almost 1 yr later, she is mad at me and says I dont care about her. I have tried to repair the friendship with no success. How do I let our other friends know we are no longer friends w/o causing more probs?