On 2020-01-13 01:43, Samuel Murray via Groups.Io wrote:
I'm not sure if one can subscribe a subgroup to the main group directly
(so that the subgroup would receive all mails that are sent to the main
group).
No, GIO will give you an "Invalid Email Address" error if you try to DirectAdd (or send a join invitation to) a GIO subgroup email address. (or top-level group for that matter)
However, if one wants to have it to where a special notice sent on the main group also gets automatically sent to one or more of the subgroups, one could set up a system using a Google account and forwarding to accomplish this; not the most elegant solution but it can work.
Cheers,
Christos
Christos Psarras