Do I have to create email group one-at-a-time??

I've sent emails to a group of 60-100 addresses for this club that I'm in by
cut/paste from previous emails that I have sent. Unfortunately, the long
list of addresses has evolved over about a year and is not a contact "group."
I now want to subcategorize to subgroups and also have a list to all
members. Having become smarter, I want these to be named groups rather than
needing to cut/paste/add/delete.

I'm trying to create my first sub group by pasting the entire group to a
named group list and then delete certain members. I can create and name the
new group, but the only way that I can see to add members is one address at a
time. Is there not a way to bulk-paste a bunch of email addresses into the
"contacts" box?

Thanks