team members,
At the moment, I’m customizing DHIS2 to collect data for a few new implementing partners, so I needed to assign a specific attribute to a particular organizational unit so that they could collect their data specifically with the implementing partners. I also didn’t want the attribute to be displayed for other organizational units that collect the same data set on their own.
thank you
Welcome back to the community! 
In this case the implementing partners is a category combination which has a one or more categories, and in the category the list of implementing partners which are the category options, so to control access which users are able to view the options, you need to change the sharing settings for the category options.
Once you have restricted the category option set to only the users who are able to view/edit the data then all the other users in who are assigned to any OU will not be able to view the options. 