Unfortunately groups can't be redirected being as there is no ID number in the URL.
If your VBSEO was setup to actually put a userid in the URL for your Member's profile pages then you are really lucky because I've never seen a VBSEO setup that actually did that- and without the userid in the URL you would be out of luck there too.
However given the example URL you provided:
Code:
http://www.site.com/members/user-5.html
Try this rewrite rule
Code:
RewriteRule members/.+-(\d)\.html http://www.site.com/member.php?u=$1 [L,R=301]
If that's not it, it's close. If you can post an actual link it might help if I need to fix it.