I think this is the answer you are looking for:
One-minute closing scene where daughter comments that Society does not say can?t go
So the "Society does not say" you "can't go". But what they say is designed to make you feel that it would be inappropriate to go. This is their M.O. on sooooo many things.
Bottom line, you "can go". The "Society does not say" you "can't go".
By the way, do you absolutely have to inform your family that you're going to this wedding? What they don't know they can't give you grief over. Personally, I wouldn't tell them. If they don't know that you're going to be in town, they'll have no reason to go checking out the Catholic weddings that day to make sure you aren't going inside the church. I don't know how many times my parents have come to the city where I live to attend JW functions without informing me that they were going to be here. I found out about the visits after the fact.
Remember: Theocratic War Strategy? dictates that
"While malicious lying is definitely condemned in the Bible, this does not mean that a person is under obligation to divulge truthful information to people who are not entitled to it." (Insight Volume 2, p. 245, 2nd column, 2nd paragraph - "LIE")
Love, Scully