Imagine the scene: Prior to the beginning of your meeting, you see people congratulating and hugging the happy couple. What do you do? Stand in the corner? Then as prayers are offered at the opening of the meeting, someone offers a prayer of thanks for the recently blessed ones? Do you say, "Amen"? As the meeting progresses and people talk about budgets, plans, things going on in their parish, and how things are going so swimmingly well, do you think, "Who are they kidding?"
The above hypothetical situation certainly sounds like it would create an uncomfortable tension.
If you know that your presence might make them uncomfortable, does your participation violate the "love one another" rule?
Non-participation might be the best option, but you should in some way make it known to the powers that be that your refusal to participate is based on a "love thy neighbor" rationale.
Your communication will not change the behavior of those who endorse same-sex blessings or marriage, but might open the eyes of the uninformed that such blessings and marriage are contrary to scripture and the Church has no business performing them.
Love your neighbor so much as to not enable behaviors that may lead others into sin.