I think that even though we can draw a relationship between an Archimate Group and other Archimate elements, we cannot say that the elements are belong to the Group because the current EA Boundary (the base of the Archimate Group) is just a graphical object. Even if we move an object into the boundary in a diagram, we have no way to confirm that the boundary has (contains) the object as model (without diagram presentation). We cannot see the relationships between the Group and elements in the Group in the current EA features.
The fact that you cannot see whether there is a relationship defined between the ArchiMate Grouping and its contained elements is part of the ArchiMate specification and very similar to the nesting of elements when using Composition or Aggregation relationships. If you enlarge an element and drop some other elements within its boundaries, the Composition relations are not shown on the diagram which is according to the specification.
If an Archimate Group were extended from another type e.g., Class, we could confirm a parent-child relationship in the Browser and in the Traceability window when we move an object into an Archimate Group. But to apply this implementation, there must be a constraint that an object can be belong to at most 1 Group. I could not find such a constraint like this.
Why should there be a constraint that an object can only belong to at most 1 Grouping? There is no such constraint on other relationships like Composition or Aggregation. And I think it is possible to have a single element to belong to more groups. Even when using the drawing option, it is possible to draw a (very) large group containing more groups each containing other elements. The inner elements then should belong to both groups.
So, concluding, I believe both options should be available:
- ArchiMate Grouping as a separate Element type which can be re-used and moved around like other ArchiMate elements.
- Visual grouping as implemented now with only visual impact and stored in the ... folder.
Possible solution to add the ArchiMate Grouping as element to the ArchiMate MDG implementation?