I'm not an expert at all so I'll try to explain my problem clearly.
I've a domain that I manage with cPanel. I've also an Office 365 solution I suscribed directy on the microsoft website. When I did the step by step procedure to get started with O365, I created all the CNAME DNS entries, add their MX and then earase the default MX (the local one) on cPanel.
But in our company, we have about 10 mailbox, but only 6 need exchange.
So I re-created the local MX and tried to change the priority to see what happened. After doing that and read some more about how MX works on Wikipedia, I understood that It will never going to work.
So I'm wondering :
1). Is there any way to create a rule, I don't know where, to say to the server : "hey catch this e-mail, go check in the 0 priority MX (the local one) if there is a mailbox that match to deliver it and if not send it to the 5 priority MX (the O365 one) ?
2). Is someone see another solution to do that ?