InfoPath Dev

Hi, I have a People Picker where Multiple users will be selected. I want to capture their usernames/Employee IDs in a text box. When I tried using Account ID, I only get the first user's Employee ID. Is there a way to get all the user's employee ID separated by a comma (,)? Thank you

 You'll need to use what is often called a double eval formula. Here's a link that describes this approach: https://blogs.msdn.microsoft.com/infopath/2006/04/05/email-submit-to-line-loops-in-formulas