You're quite right, but there's always a soft option.

I'm a Quaker, married to a practicing Catholic. When we got married, we refused (for obvious reasons) to include a mass which, by its definition would exclude me and half of the people there (i.e. my family etc.).

This caused a small storm in Liz's family, but she simply offered to go to mass with anyone who wanted to come earlier in the day.

In this way, the people who wanted the mass got it, without it causing any problems.

I think you could organise an optional, low key mass in support of the event, but not as an official part of it.

How could anyone object?

:-)