I was able to solve this by putting my list [subject-list] shortcode in the To: field in Mail section.
Here’s a little more detail:
My Form with Pick List containing Pipes for mail recipients:
<p>Subject (required)<br />
[select* subject-list include_blank "Customer Service | Customer Service <help@mycompany.com>" "Sales & Business Development | Sales Team <sales@mycompany.com>" "Media | Person One <person1@mycompany.com>, Person Two <person2@mycompany.com>, Person Three <person3@mycompany.com>," "Client Services | Person One <person1@mycompany.com>, Person Two <person2@mycompany.com>, Person Three <person3@mycompany.com>, Person Four <person4@mycompany.com>"] </p>
I then just set the To: field to [subject-list]
I used [_raw_subject-list] in the Subject field of the Mail template to help the recipient understand the context of the mail they were receiving.
