When it comes to ensuring a secure IT environment, applying user password policies is crucial. In Windows 2008 R2 Domain Controller, you have the ability to set specific password policies for different user groups, providing an added layer of security. Here's how you can apply a user password policy for a user group in Windows 2008 R2 Domain Controller:

1. Open the Group Policy Management Console by typing 'gpmc.msc' in the Run dialog box.
2. Navigate to the 'Group Policy Objects' node, right-click, and select 'New' to create a new Group Policy Object (GPO).
3. Link the new GPO to the domain or organizational unit (OU) where the user group is located.
4. Right-click on the new GPO and select 'Edit' to open the Group Policy Management Editor.
5. Go to 'Computer Configuration' > 'Policies' > 'Windows Settings' > 'Security Settings' > 'Account Policies' > 'Password Policy'.
6. Here, you can configure password policy settings such as password length, complexity requirements, expiration, and more.
7. Adjust the settings according to the password policy you want to apply to the specific user group.
8. Close the Group Policy Management Editor and wait for the policy to propagate across the domain.

By following these steps, you can enforce a customized password policy for a specific user group in your Windows 2008 R2 Domain Controller, enhancing the overall security of your IT infrastructure.