Can I send emails only to contacts with a specific relationship attribute

I want to send an email to org contacts that have a relationship attribute for an upcoming event that is by invite only. I thought if I add a query narrowing to those contacts, and check the relationship box and all those relationships listed, that online express will only email to the contacts with that relationship attribute.


I am only now learning that it does not. It mails to ALL relationships checked, with OR WITHOUT that relationship attribute for an upcoming event.


For now, I am just going to export those emails and push them through our company email. 


I would like a workaround for future reference.


Anyone have a work around??