I have a group with about 20 contacts.  I'd like to delete 10 contacts and add 5.  Is there an easy way to do this?

I believe the hard way is to write down on paper a list of the 10 to be deleted and 5 to be added, then go down the list of contacts unchecking or checking individually, as appropriate, their existence in the group.

Also, is there any way to view/list which contacts are in a group -- short of entering and expanding the group name as an addressee in a new email?