Linking an Entity to a Virtual Entity

Hi, this is my use case:

I have Contacts information that is an Entity, in it have the standard details such as name, email, phone number, etc.

I then have a "ContactsExtended" entity which is set up as a Virtual Entity.

I want to link the two via an id of some sort (e.g. specify a field called ContactsId that resides in both Contacts & ContactsExtended)

I was wondering if it is possible to set it up such that when I view a particular Contact entity, it will automatically pull in all additionally information from ContactsExtended via the "ContactsId" link.

Any help would be much appreciated!