Wish: SUSHI allows to define (custom) complex-types

(being pretty new to FHIR and SUSHI) I learned that using FHIR Shorthand (and SUSHI) I can generate FHIR artefacts e.g. to define FHIR StructureDefinition of these "kind"s:

- "resource" (a new FHIR Resource via FSH Item Declaration statement `Resource: MyNewResource`)
- "logical" (a new FHIR Logical Model via FSH Item Declaration statement `Logical: MyNewLogical`).

Now I want to define a new complex-type that I can reuse in multiple custom Resource definitions. Currently I have not seen a way to achieve this using FHIR Shorthand syntax.

Question/Wish:
If there really is no way yet to achieve this in SUSHI (maybe I just didn't try the right thing), would such an enhancement make sense at all?

Start by reviewing SUSHI's handling of FSH Item Declaration statements for Resource and Logical items, along with the FHIR Shorthand documentation for supported artifact kinds. Determine the syntax and compiler behavior needed for reusable custom complex-types; done means a documented approach exists and SUSHI generates the corresponding FHIR artifacts.

Written by the indexing model from the issue text.