Request Referance or ticket only registration

[xplove]

hi there.
just wonder is there any add on for new registration only allowed from if users of that site send ticket to someone or referance?
dont even know if explaned well
thank you in advance

 

[THB]

sr. i don't speak englist very well.
see picture:

 

[xplove]

Thank for your help but its not what i am talking about. or i didint explane myself good.
we are closed our forum for new members. but our members want to invite they are trusted friends. so is there private invite addon as like in vbulletin.