Design Patterns for some common entities

I have a situation where I have 4 classes. 3 of them share a property but one doesn't

If they all shared it I would of created an abstract class with the property in as I'm trying to find common ground.

What can I do in this situation? The only thing I can think of is to have it as an interface and then have it implemented by the classes that do share it.

Any other ideas?

Thanks