This is more of a theoretical question, but is it possible to dynamically, and on an ongoing basis, adjust the priority of emails in the mail queue?

For example, for all mail, set it's priority (p) to 1 (meaning send immediately). If N emails in the last M share similar or identical content, adjust the priority of this email such that it's priority is in the range [0..1] so that p is equal to 1 - N/M and other email can get sent before the similar/identical stuff.

Or, if you have another idea or standard what is it?

Some background: Someone put a mail() call in an infinite loop... And now we have to wait for the mail queue to catch up before anyone can send or receive mail again.