In Service Studio you can use structures that are exposed by a different eSpace or extension, called, in this context, a Producer. Simply add these structures as eSpace references for your eSpace, called, in this context, a Consumer eSpace.
How to Add a Structure Reference:
How structures are handled
Once a structure is added as a reference in the Consumer eSpace, you can use it like any structure originally created in your eSpace. However, you cannot change the definition of the structure or its attributes.
Add/Remove eSpace References | Expose a Structure