HI,
New to powerapps and this forum so apologies if this has been answered or my post etiquette is not right.
I have an app designed for mailing selected customers to a major incident of our product.

This has a data source of a list called 'Major Incident Comms Matrix' that has a concatenated formula for column "emaildistrib" on all emails.

On the app there is a listbox called customerBox(heighted in red) that filters the 'Major Incident Comms Matrix' list based on the product dropdown = 1.
What i am trying to achieve is an email distribution list based on the 'Major Incident Comms Matrix'.emaildistrib column for all values selected from the customerbox listbox. This needs to be concatenated into one email BCC distribution and will be sent using powerapps/powerautomate.
could anyone give me some pointers?