Region lock and group giveaway

As far as I know - no.

Edit: Yes, only users that are the group(s) and region(s) can enter the GA.

Edit 2: Nur deutsche Nutzer der drei Gruppen sollten in dein GA kommen.

Those work differently. If giveaway has a region lock, and you are in another region - you can open this giveaway, but can't enter.
If giveaway is for a group, and you are not in this group - you can't even open it, you will get "Error: You do not have permission to view this giveaway, since you are not a member of the required Steam groups."
So, if you are in group, but in another region - you will be able to open, but won't be able to enter