I recently needed to have a form send emails to multiple users selected from the people picker tool. The first issue I had was the accounted had lots of unwanted and unhelpful text within i.e i:0#.w|domain\MUDID;
Doing some searching I found a code to strip out the unwanted bits and just leave the MUDID, semi colon separated, I used this and it didn't resolve the names when sent, so it needed the email added to the accountid to work, so [email protected]
The code strips out the beginning characters so 18 characters removes everything up to the MUDID from the example above and then appends the email part to the remaining MUDID separated by semi colons
eval(eval(eval(AccountId, "substring(., 18)"), 'concat(., "@email.com;")'), "..")
This gives the following in a text box i.e [email protected];[email protected];[email protected]
I tried up to 13 names in the people picker and then used this field as the To in an email connection and all people received an email, you may have to start with 0 instead of 18 in the code and then adjust to strip out all the unnecessary text