Well I don’t have a script for you, but perhaps you can simply use the features already in the Domino Administrator to set the “Explicit Policy” in the Person documents for a Group of users.
You will have to create one or more Groups in the directory to use this tool.
In Domino Administrator 6.5.x or later, connect to your Admin Server and open the Groups view in the People & Groups tab (the default). Click the “Tools > Groups > Assign Policy…” action to open the dialog for “Assign Policy Options”. Follow the instructions on the dialog box and click OK.
You may also assign a policy to selected People using the tool for People.