Example:
sent campaign email message to 400 Targets
issue: server restriction: Max emails sent per hour on server is 200
Sugar queue sends all 400 in any case (in batches of 150)

Results:
200 succeeded
but 200 Inbox messages (returned as unsent due to exceeded quota)
Sugar now thinks 400 were sent successfully

What is best practice here in order to build a list of the 200 failed sends
I would prefer not to read each unsent email and then search for each Target and then add them to a new target list...
It appears that they are sent in a random fashion (e.g. not by tracker key or ID) so cannot mass sort/delete 1st 200 from new queue etc....