How to override the (final) equals method in java enums?

I have a problem with overriding the equals method in an Enum to make it compatible with other classes. The Enum implements an interface and the idea is that all implementations of this interface can be tested for equality, regardless of their type. For Example:

public interface Group {
    public Point[] getCoordinates();
}

public enum BasicGroups implements Group {
    a,b,c; // simplified, they actually have constructors
    // + fields and methods
}

public class OtherGroup implements Group {
    // fields and methods
}

If both a BasicGroup and an OtherGroup have the same coordinates (in arbitrary order) then the equals method should return true.

No problem when performing myOtherGroup.equals(BasicGroup.a) but since the equals method in Enums is final, I can't override them.

Is there some way to work around this? Like when testing on another BasicGroup the default equals method (reference equality) is used and when testing other classes my own implementation is used. And how do I make sure that java doesn't use the wrong one when I do BasicGroup.a.equals(myOtherGroup)?