How to Disable Delivery – Read Receipts

Is there a way in the Exchange 5.5 administrator, to DISABLE the request for ‘delivery’ and ‘read’ receipts for any, or all of the users in the global address list? We have the possible missuse by users to send messages to
ALL users in the GAL, requesting delivery and read receipts. This has the potential of bringing the exchange server to is knees. Does anyone have a fix, or the information to disable this feature from the exchange server. We know how to disable on each client using Outlook, but want to know a way from the exchange administrator.

Thanks