What you could do is click the Users tab and in the search type the Group Name, which should bring up all users within the group you've searched. Note that you may have to make some amendments if the Group name happens to reflect someone's email address or some field (i.e if they group is "Leaders" and you have john@ leaders.com but john isn't in that group, he will show up in the search). Select all relevant parties (uncheck any that overlap from other departments) then export them.
As @VasilisV_3CX has implied, there is not a simple way to do it. You can do it with the Call Control API, but that would be more work than just recreating the groups manually.
We have a REST API that can do it, but there is a cost associated with that...