Gnupg good for big groups?

[Snaky Love]

Hi,

I would like to better understand: is gnupg good for big groups?

I would like to encrypt communication in groups - not instant communication
like e.g. messengers like pidgin, but like on a forum or web-group - the
data persists in an archive,  where the communication can be read. Members
are coming and leaving a group constantly - that means if somebody leaves
the group, she should not be able to read the content decrypted anymore, and
if anybody attaches the group all the old content optionally must be
encrypted with her key so she can read all data belonging to this group.
well, maybe you get the idea. It´s basically like a forum or mailing list
with an archive.

With my understanding of gnupg I see no other way than to store the data NOT
encrypted - in a database or wherever, perhaps on an encrypted disc to
compensate for the data not being encrypted - and then to encrypt the data
on the fly with the pubkey of the user after the user logged into the
website and is checked to belong to the right group.

But doing this would be stupid, as it would basically use gnupg only for
transport - but there is already SSL and TLS existing for this purpose.

So is there any trick to encrypt data at creation time for unknown future
users?
And how can I remove users from the group of allowed users without
re-encrypting the content? Is this possible to realize at all without having
to keep the original unencrypted content?

Is this scenario - group communication - not a use-case for gnupg at all?

Thank you very much for your attention!

Have a nice day,
Snaky
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