Storing Site Locations as Contacts vs Child Customers

We ship signs to site locations owned by customer X. Customer X can have one site or in most cases dozens. Our site locations are currently stored on the Sales Order as a free-form text field, not easily searchable. We are trying to find a way to group and store these locations. We tried making 50 or so sites child customers of Customer X, but this doesn’t seem like a good solution for us – a customer could have a hundred sites (one user peeve is that the global search returns too many results). What is the best way to store these site locations in NS so they are easily searchable by customer? Can we make them contacts? How do others do this? One other thing to note is that site owners can change frequently.