First of all...I would try my best to explain the reason as to why attending events in a mixed gathering environment is highly prohibited in islam...
1. Attending a wedding in our community is just like dressing up to look the best of all and this means dressing unislamically and immodestly, and when the wedding isn't separated, it opens up the door to improper mixing.
Why should we allow it to happen more easily? Sure, we can't enforce hijab and feelings of modesty on any sole individual or prevent our friend's daughters from showing up in such clothes but we can certainly prevent much of the mixing that goes on when it comes time for us to host a wedding....
Also, why are we so quick to display the bride to hundreds of guests without any qualms? i know of someone who told me about an event she attended where the groom's male cousin was chosen to give a speech in which he said, I had always heard that your wife was pretty, but I never knew she was this beautiful.
Fathers, brothers, and husbands, we need to ask ourselves, Is this what we want for our communities daughters?
In the end, one can argue that even if one were to separate their wedding party, illicit gazes can still occur in some nook of the event. But it's not an “all or nothing” type goal. It's about doing the best you can.
Weddings are a big ordeal for all of us, and we all want things to be just right. After all, it's “just one day.” If your family is not sure on whether to separate this event or not, perhaps it would be best to
consider the reasons mentioned when making your decision for the big day. If it's “just one day,” then best we do that day right.
We ask Allah (swt) to help us run our weddings in ways that please Him and not in ways that may harbor His displeasure.
...being in hijab would be very difficult for one to maintain but personally i have had weddings in my family where i refused to attend...due to the same reasons....