Adding a user to different permission groups within same site collection?

Question

This is for sharepoint 2019 enterprise on-premise.

What i am having to build is a site in which every site and subsite has its own unique access permission groups. Creating the site and subsite and telling the subsites to not inherit was the easy part. the hard part is finding out how i can add or update a users permissions across multiple subsites within the same site collection.

\ Main Owners Group Members Group Visitors Group

Subsite A
    Subsite A Owners Group
    Subsite A Members Group
    Subsite A Visitors Group

    Subsite A-1
        Subsite A-1 Owners Group
        Subsite A-1 Members Group
        Subsite A-1 Visitors Group

    Subsite A-2
        Subsite A-2 Owners Group
        Subsite A-2 Members Group
        Subsite A-2 Visitors Group

So i want to add a user to have read only access to the main site /, Subsite A and Subsite A-1 but not subsite A-2 but the only way so far seems to be manually going to each subsite within the collection, click on the visitors group and adding the user. what am i missing?

Answer 1

The possibilities to manage the group memberships would be:

1. Add user to groups manually

2. Write a script or a "program" to add the user to the groups (but needs the input to which groups)

3. Use a third-party tool to add the user to the groups (also still needs the input to which groups)

Actually the groups of all sites show up in the root site (or any of the subsites) when going to Site Settings > People and groups > More..., so no need to go into each subsite individually.

Answer 2

I was afraid of that. the site collection has 1 site with currently over 20 subsites and each subsite with a by-design broken permissions forcing the need for explicit access.

Thinking about it i could create a list that only the site "owners" access and then add each site/subsite group as maybe multi selection checkboxes in that list. The site owners could then add the user(s) to the list and check off the access items. We export the list as a csv and then all i need to do is write a powershell script that would read the CSV and put the user in the groups based on the selections exported...

eh well time to start searching some more :)

thanks!