Wedding Etiquette. . .have a question

I have a friend whose daughter is getting married this summer. My friend is divorced and remarried, as is her ex husband (the father). My friend asked her daughter if she was planning on acknowledging her step father at all during either the ceremony or reception and was told "no, I'm not taking anything away from Dad'. Dad is walking her down the aisle and giving her away, and there will be only one father/daughter dance between the two of them. My friend is kind of torn because as a mother, she knows this is her daughter's day so she doesn't want to push the issue but on the flip side, her new husband has been part of the family for many years and knows he will be hurt at the slight.

I'm curious if there is any 'etiquette' regarding how to acknowledge all parents involved in a divorce situation? Has anyone been involved or heard of how this situation has been handled before to avoid hurt feelings if possible? My friend asked me what she should do but I didn't really know what to tell her as I don't have much experience in that area.
Just curious what other opinions are. . . .