First go to the Teams screen in the People tab; tap
Edit>New Team and then tap on the new team (e.g. "Group1")
to edit the name. Hit Done, then tap on the group name. If the individual
folks are already in the app, just tap on them to include them. If not, tap on
Add New People
at the bottom of the list.
You then have a choice: hit
Select From Contacts to
choose from your device's contact list, OR type the names
into the big field, OR copy and paste from another source. As it says, you can
separate names with commas or returns (use quotes to include a comma within a
name). So: John Doe, "John Dozer, MD", Michael Smith
After any name, you can add an <email address> in brackets. For example, John Smith<email@example.com> Conveniently, this is the format that email apps use, so you should be able to cut/paste directly from a To: or cc: line.
Tip: If you have a master list as text, copy and paste it into the import field, but be sure to do it in All People to avoid adding everyone to a particular group. Then you can create each group and assign each person to the appropriate group (or more than one).