Remove users from Remote Desktop users

hi

for past months , every time we created a new PC we added some users in the Remote desktop users ( including user himself ) , now we have a new security policy that avoid the user to be in RDU list , how can i remove the users and keep others through GP ? i know how to add , but remove its not work for me.

in simple word i need to create policy , and put name in it , then deploy that policy to over wright the current names.

Osma Othman