join(collect) e-mail addresses with multiple e-mail addresses is not recognized as e-mail address.

Please see attachment for explanation of the problem. I hope somebody can help me with this. i have tried several way's, but unable to get it to work.

The purpose is controlling access to a dynamic sheet, where based on an account the user can only see his account data and not other accounts. Because the employees switch/leafe/join the company i use a reference sheet where i manage the user per account and then based on the join(collect) define which account your working for and determing if you get access.