Exchange 2003 Email Attachment Software?

[WinNT511]

We have a exchange server 2003 SP2 installed on a Windows 2003 R2 SP2 box. As of the last few days users have emailed 1 attahcment with a size of 750 kb which brought our ISP Line to a slow crawl. The email was to a dist. group with 150-175 email accounts populated in it.

I am looking for some software package the interfaces with the Exchange server that will give us control over when email attachments can be sent during outside business hours. I am unware of any GPO functions that could achieve this goal.

Please advise...

 

[xmsre]

Don't need third party software. Use an smtp connector.

http://support.microsoft.com/kb/294736/en-us

http://support.microsoft.com/kb/265293/en-us

http://support.microsoft.com/kb/555260/en-us