Set network proxy by group on Open Directory I have an OS X Server with Open Directory. I am wondering if there is a way a group can be set to use a proxy when a user from that group logs in, and to remove the proxy if a user from a different group logs in.

Edit:
What I need to do is if User A (in Group A) logs in, an HTTP and HTTPS proxy is configured. But if User B (in Group B) logs in, the HTTP and HTTPS proxy is removed. I was able to set it up as explained below, however, I can only change the proxy settings for Wi-Fi adapters, the Ethernet adapter does not have proxy settings. The global HTTP proxy option only proxies HTTP but not HTTPS protocols allowing users to view blacklisted sites on HTTPS.

Is there any way to apply proxy settings on Ethernet, or any other way to apply HTTP and HTTPS proxy settings?
Yes.

You will have to use Profile Manager and manage the settings on the Mac. Set up a default profile with the default proxy settings for the managed Mac.

You can then set the profile for any of the groups you create in Open Directory to override those settings.

A Profile Manager tutorial is a little beyond an answer here but check out:

http://www.apple.com/au/support/lionserver/profilemanager/

and 

http://krypted.com/mac-security/configuring-using-profile-manager-2-in-os-x-mountain-lion-server/

For the Ethernet proxy settings you will have to use a Custom Settings payload. The Ethernet proxy settings are in /Library/Preferences/SystemConfiguration/preferences.plist so you will have to import them once with no proxies set then set the proxies and import them into the second profile.

You will find Custom Settings at the bottom of the settings list on the left of the Profile Manager screen.