We currently have a 50mb limit for email size set through connectors. We have a subset of users that must be restricted to only sending 15mb emails.
I have tried using a Transport Rule, but there is no option for message size, only attachment size. If I limit it to a 15mb attachment, they can still attach as many 1mb files as they want. It never violates the rule, because no single attachment is larger than 15mb.
We can put the users in their own database but then we can only limit mailbox sizes, not send receive sizes.
Any ideas?