This functionality is already given right out of the Wix-Box.
It is called → ROLES + BADGES. Using these you can generate your own PERMISSIONS to every single PAGE of your Wix-Website.
To learn more about it, take a look here…
https://www.wix.com/velo/reference/wix-users-backend/badges
https://www.wix.com/velo/reference/wix-users-backend/roles
Also you will need to be able to work with Wix-CRM and PMD(public/private).
https://www.wix.com/velo/reference/wix-crm
If you want to see a possible solution to all your wishes, take a look here to the soon coming Multi-Login-Management-System…(including all the functions) 
https://russian-dima.wixsite.com/login-system/vnloginmgm
If the one or the other FEATURE is not available or do not work → IN DEVELOPEMENT!
Have fun!
BTW: You will find some more informations in the READ-ME-PAGE to be found in the ABOUT-SECTION of SETUP.