Create Mail Group List without Contacts

Is there a way to create a MAIL Group List without adding all the emails to my CONTACTS app? I’m in a writer’s group of over 100 members, and I don’t want all of them as contacts on my phone or MacBook. I just want it them in MAIL.

In Outlook, I used to be able to quickly and easily create large or small Group Lists by opening an email that already contains most or all of the email addresses you want to include. Then, you can simply copy and paste those email addresses into the new Group List window.

I’ve tried every way I can think of in MAIL to no avail.

While I’m not a techie, I’m not a novice either.

TIA