branch destination at first login after registration modification

Hello,
our site requires to have a ES page for any user to have the information/content displayed the way we like/need.

Do to the fact that it would not possible to force the user while registration to create a page, I like to have modified the branch destination while the user's first login to the NEW page creation site.
Could you be so kind and give me a hint where to modify the login process to change the link target (it should be anywhere implemented at user registration confirmation process ???) . This would be a one time diversion for the user, just after it's first registration.
The King's quest in this case would be to have this behavior modified by usergroup, but that is not a mandatory criteria... ;-)

OR

second idea is to implement a check if a page already exists for the user at every login and if not, to redirect him to the new page creation site - but for this case I mandatory need that this check could be performed for selected user group only.

If there wouldn't be an simple way to have this implemented - you may do this for me as a paid custom mod?

Best regards