I have a SharePoint list which all members of a specific group have 'Contribute' access to by default, i.e. they all need to be able to create new items.
One of the fields in the SharePoint list is a person/group field. If a person's name is selected and the record is saved, then that person should no longer be able to edit that specific item, as it needs approval fields to be completed by another person in the group.
I'm trying to change the permissions on the item by using the action 'Stop sharing an item or file' and then 'Grant access to an item or folder'. What I need to do is to give the group 'Contribute' permissions but override this for the named user above with 'Read' permissions only. I have tried adding a second 'Grant access..' action targeted at the individual, but the 'Read' permission has no effect if they already have 'Contribute' permission via group membership.
I can't work out a way to get the individual permission to override the group permission. Removing them from the group is not really an option as it is used elsewhere.
Is this even possible or will I need to approach this in a different way? The forms have been customised in Powerapps, so a fall back option is to lock down the fields, but that is a very messy and time consuming approach given the number of fields in the form.
