How to get in-app subscription group informations

Hi everyone,

I am successfully using App Store Connect API to get diverse informations about my apps.

But I don't find any endpoint in documentation that can give me the in-app purchases subscription group informations of my auto-renewable product.

Can someone tell me if such a endpoint exists ?
And if not, it is possible to claim an update of the API including this feature to Apple ?

Thanks in advance.