There is a way, but it qualifies as a kludge with a capial K.
Click on the 'Contacts' icon on the toolbar of Win Mail. If you don't have
one, right click the toolbar and select customize from the menu. Add
'Contacts' then click on it.
You get a copy of what was called windows explorer that is open to your
contacts folder. You should see the sub folders. Navigate to the group of
contacts and select one or more (use control click or shift click to select).
Then right click on one of the selected items and select Action->Send E Mail.
THis creates a message with the selected contacts in the 'To' line. You can
then cut and paste to move them to the cc or bcc lines.
If you want to select contacts from more than one group, create a separate
email for each group then cut and paste the names into one of them.
See, Microsoft didn't remove functionality, just hid it and made it user
hostile. Great going guys ! ! !
Mike