[support] How can I restrict certain strings in login names during registration (6.x)?

Hi, I'm looking for a possibility to restrict login names during registration, i.e. I want to forbid using strings "abc" or "ABC" on whatever position in the login names they pick. How could I do that? But I do not want to block those strings in login-name generally, just only during registration... Jarry -- _______________________________________________________________ This mailbox accepts e-mails only from selected mailing-lists! Everything else is considered to be spam and therefore deleted.