When I dressed my Hannah Anna up as a Berner bride (to create -- at the request of my step daughter-in-law -- an invitation to a day-after-the-wedding family reception for 75 of her relatives), I finally resorted to putting elastic on a white confirmation veil and running it under the "chin". Hannah wasn't thrilled, but it worked long enough to get a priceless picture of a the bride (with pearl necklace -- a gift from the groom), Thor (her Great Pyrenees groom, donning bow tie and French cuffs), Molly (her Great Pyrenees maid of honor, wearing a pastel pink head piece and pink necklace) and the officiating priest (Devon, the Doberman with clerical collar). Clare, the Harlequin Great Dane, was a stand-in for Mother of the Bride. The caption on the invitation was -- "This wedding has gone to the dogs."
On a serious note, you can use black elastic -- which might blend in with the fur better. Nancy Melone Mars, PA