When importing contact data, the user should be able to multi-select existing groups which the new contacts should be added to, and/or have the option of creating a new group from the imported set.
We may want a new separate step in the wizard for this - but for now you can toss it onto the Preview step:
[ ] Add imported contacts to existing Group(s) [v - select group - ]
[ ] Create a new Group and add imported contact to this Group
Select group control is scrollable div of checkbox rows as in Search forms - so user can check on or several groups easily.
I think we can include CRM/Group/Form/Edit.tpl in the import preview template in a hidden block, and then If 'create new group' is checked - unhide it (display: block).