Need to be able to bulk message direct from the gradebook

I'm just looking at students performance across a range of assessments and I need to now be able to message those who are poor in one or other of several categories to tell them to come to extra revision. No easy way to do it for all at once though.

If there was a checkbox by each student's name and a dropdown at the bottom exactly as there is on the browse user accounts page allowing a note to be added or a message to be sent, then the gradebook highlighting would allow quick and very specific messages and feedback to be sent.