Mavericks Contact app - editing a distribution list (e-mail)

Hi everyone, I'm a recent returning Mac user after being gone for about 20 years so forgive me if I'm missing something obvious here, but... I have all my contacts in the Contacts app and have created a Contact Group for a list of my friends. One of them likes getting e-mail to both his work/home e-mail addresses. When I choose "Edit Distribution List..." from the Edit menu, my list of contacts is displayed and Voice Over says the e-mail addresses that will be used are shown in bold. Just wonderful! Luckily, I do have some vision so I tried to look at the list by enlarging the screen and I can't figure out how to select the work e-mail address for my friend. The one for his Home e-mail address is listed first so it is selected. I tried selecting the 2nd column - which is a group in the table containing the e-mail addresses but I can't figure out how to select or de-select the e-mail addresses. This should be an easy thing to do! There should be something available where you can choose people's e-mail addresses with check boxes. Maybe there's a better app for managing Contacts/Groups? I could just create a 2nd contact for my friend and put his work e-mail address there instead but that seems like a bit of a hack to me. Thanks, John