Prevent shared pictures from being recognized once by user

Describe the feature you'd like to request

My nextcloud instance is dedicated to my family. We share a lot of data.
There is already a fix for not analyzing several times the pictures from a group folder : https://github.com/nextcloud/recognize/pull/939

My concern is related but not the same : We have a "huge" shared photo library, 200k photos. This library is attached to a virtual "Sharing Account" user, that shares its data with all other people. I didn't use the "group folder" feature because the photo library is located in another drive, so I found this workaround in the nextcloud forum.

Now here is the problem : Recognize is classifying each photo 7 times : once per real user + once for the virtual "sharing account".
Not only this is counter productive, but I don't want (need) several users to use recognize, so this is a huge loss of time and energy.

Describe the solution you'd like

Currently the recognize feature is disabled for all users except me but the scan covers all users. As requested below, the scan should only target the enabled users or allow user targeting via a parameter.

https://github.com/nextcloud/recognize/issues/905

Describe alternatives you've considered

Another smart solution woud be to allow the sharing of the recognize data, so that all people from a nextcloud instance would benefit from a single tagging process, and a single manual curing process.

This feature request is described here : https://github.com/nextcloud/recognize/issues/948

Start by reviewing the related discussions in issues 905 and 948, then trace how the scan currently processes shared files for each user. The issue presents user targeting and shared recognition data as alternative solutions; done should mean shared pictures are not classified repeatedly while the chosen behavior remains available to all intended users.