It was a work for GNU Social.
Instead of mentioning an account with "@.." You mention a group with "!..."
And all accounts within this group will receive the notifications and see the status like if they were personally mentioned.
@fedilab ah, the good old GNU Social, I used it for many years and I always loved the groups feature.
Server run by the main developers of the project It is not focused on any particular niche interest - everyone is welcome as long as you follow our code of conduct!