How do you combine two lists?

Hi,

My organisation uses MailPoet and we make lists by importing contacts from Teamleader, based on tags we create there. Now, in Teamleader we have tags such as ‘administrators’, ‘members’, ‘non-members’, and so on. What I’d like to do is send a newsletter to only the people who are in BOTH the ‘administrators’ and ‘members’ list. Does anyone how you can do that in MailPoet? In the sending options I can only select both lists in their entirety, that’s not what I want.

Thanks!