I often get requests from users asking how they can grant access to folders in their mail file to a colleague. eg. they're working on a project and they want to share just the e-mails in one or two folders.
For a product is all about collaboration, I'm amazed there is no way to do this in Notes. You can grant access to the whole mail file, but not at any level below this, unless you want to start messing with reader fields on individual documents.
Yes, there are "workarounds" like copying & pasting the e-mails into a TeamRoom; or setting up a rule to forward the e-mail to another person, but they have numerous shortcomings.
I anticipate that this idea would require a new level of access to be defined in the database ACL (eg. 'read shared folders'), as well as something like a new folder property (eg. a "folder ACL") that would expose only the documents in the folder to the authorised user, and no other documents.
link to a similar idea:
I tried to link it below, but ended up with the wrong link (maybe because it is in a different category)