Multiple references to same interface

[georef]

One frequently has a number of classes all implmenting the same interface.

To show this neatly on a class diagram, it is conventional to use the (small) circle representation of an interface attached by a short line to the left side of a class object.

To do this one needs multiple "interface circles" on the same diagram, all referring to the same interface object.

When we try to copy and "past as link" a circle interface to achieve this representation, the action is disallowed by EA.

How should we address this rather essential diagramming need?

Thanks.