Could you clarify a bit please?
Is there something in the cell which identifies the "email"?
When you say "open a particular email" do you mean:
1. Open an email message that you have sent or received which:
a. resides in an email client somewhere or
b. was saved as a file on your hard drive (what file type?) or
2. Open a mailer edit window in your mail client in order to compose and send an email to a particular address?