Wrapping a class with additional features outside the project

I have a class in Project1 class library

class MyClass
{

[CustomAttribute]
public string prop1 {get;set;}

public string prop2 {get;set;}

}

I have: CustomAttribute depends on a 3rd party library which I dont want to include within MyClass.

Is there a way in which I can wrap the CustomAttribute of MyClass with prop1 outside the project1 and in a new wrapper project2 that includes the Project1 ?

Thanks