Very often your members of your team will hold responsibility for certain contacts in your Campus account. E.g. you might have a team of Sales Reps who prospect certain contacts.
You are able to assign a contact to any of your Campus users by editing the contact (hovering over the contact in the Contacts data grid and then clicking the Edit button. In the edit window there is a field called Owned By.
Simply click it and select the member of your team who should own that particular contact.
Once you have assigned your contacts 'owners' you're able to create contact lists based on who owns them.
There's more information about how to create a Contact List here.