eCommerce Groups endpoint: Support retrieving only root product groups

[nunoaguiar]

Is your feature request related to a problem? Please describe.

The Groups endpoint currently supports:

• Returning all product groups
• Returning the children of a specified parent group

There is currently no way to retrieve only root product groups.

Applications must retrieve every group before determining which ones have no parent.

Describe the solution you'd like

Provide a way for the existing parentGroupId parameter to explicitly request root product groups.

One possible implementation could be treating an explicit empty value (or another reserved value such as 0) as:

Return only groups without a parent.

The implementation shown above is only intended to illustrate the idea. The platform team can determine the most appropriate implementation.

Describe alternatives you've considered

Adding a custom endpoint and/or extending the current one by adding a separate query parameter such as rootOnly=true.

This may introduce ambiguity when both parentGroupId and rootOnly are supplied.

Additional context

Current behavior should remain unchanged:

• Parent specified → return children
• No parent specified → current behavior

The request only addresses the missing ability to retrieve root groups directly.

Best Regards,
Nuno