See below pic adding a contact to serveradmin\ Companyname\ Exch2016_Base\ Hosted Organizations\ DomainName \ Contacts
works but when you pull up the new contact added in the Global Address Book on outlook or OWA and want to add that contact to your personal contact list the email is not test@test.com but test@DomainName.com, in which the DomainName is equial to the company domain name you are hosting on Exchange 2016
and this is was it looks like when adding that contact to your personal contacts, it shows the email address associated with the domain you are hosting and not the domain you put in for the contact email.
The best recommended way to achieve this is by using a Public Folder.
A good howto can be found here: https://www.cogmotive.com/blog/office-365-tips/create-a-company-shared-contacts-folder-in-office-365
Even though the howto is written for office 365 it works pretty much the same for Exchange 2013 / 2016 with outlook.
Just make sure you create the public folder inside SolidCP, assign the rights using SolidCP and then follow the outlook steps as in the manual.