Restricting frequency of POP3 connects

[Prasenjeet Pati]

Hi All, I would like to restrict the frequency of POP3 check on my mail domain in order to restrict users from checking for emails every 1 min or sometimes even more frequently.   Can someone please give me some reference to any such patch/ code available that I can use with QMail + VPopmail.   Thanks in advance.   Warm regards   Prasenjeet Pati