1 - Create a Cloud config group and add all the APs that will have the 2.4G radio disabled into that group.
2 - In the network policy > Device template, Create a new template for the APs and make the necessary changes to the radio settings.
3 - Once you save the settings (youshould still be on the Device Templates page) add a classification rule > In the Classification rule click on the add (+) sign > cloud Config Group > Contains > Select > Select the CCG you created earlier > Save.
Now you should be able to see the Template with the classification rule > Deploy.
I hope this helps.