Querying Appeals tied to BBIS emails

Hello all, I am trying to query appeals tied to specific BBIS emails, but in a Constituent query I can get to the BBIS email but not the associated appeal. In an Appeal query, I cannot get to BBIS emails. I know that the email in question is tied to the appeal, it shows up on the appeal's Mailing tab in CRM, but is there a way to query from the front-end? 


Excuse my ignorance, I am fairly new at this. Thank you all so much for your help!