The best way to keep from being marked is to not share your personal life with anyone. If they have no information - they will make stuff up to fill in the blanks - but it won't be anything they have evidence of - it will be more along the lines of you being materialistic or too private or whatever. The more friendly you can be at the meetings without revealing personal information the more confused they will become and eventually, they may leave you alone all together. If you are always "busy" eventually they will stop trying to socialize with you.
Just my 2 cents.
bafh