ON the iPhone in Settings > Messages restrict the Send and Receive to just the iPhone Number (you don't need to Sign Out of the Apple ID just set so it is not active.
DO the reverse on the Mac in Preferences > Accounts for the iMessages Account except Allow the Apple ID and not the iPhone Number.
So now the iPhne can only receive item addressed to the iPhone Number and the Mac only items addressed to the Apple ID.
On the Mac start an New Messages and manually add the iPhone Number including Country Code to the "To" spot (if you type in your Name it will not call up the My Card from Contacts).
Send an iMessage to the iPhone.
If it does not go or does not arrive then you need to go here When the iMessages account will not Login
If it worked re-enable the deactived IDs on each device.
9:34 pm Thursday; November 16, 2017
iMac 2.5Ghz i5 2011 (Sierra)
G4/1GhzDual MDD (Leopard 10.5.8)
MacBookPro 2Gb (Snow Leopard 10.6.8)
Mac OS X (10.6.8),
iPhone 6 iOS 11.x and an iPad (2)