Find all ideas voted on by someone from a specific email domain

When preparing for a face to face meeting with a customer it's useful to know as much as possible about enhancements they have requested. In order to to that I need a way to find all ideas voted on by someone from the customers email domain.

I've found two option that looks like they would address this need:

1) I search for portal user by email domain, but that will only return ideas *created* by someone from that domain. I need a way to get to all ideas *voted" on from a particular domain.

2) I can search for all ideas voted on by specific person, but that does not give me a lost of ever submission from that domain.