Hi Jeff Sterup,
Refer to this thread http://wordpress.org/support/topic/disable-front-end-plugins-from-loading-in-admin-area?replies=7. It had worked before but now cannot worked for me.
I had enabled all option in Plugin Organizer's setting.
Currently I cannot disabled plugin in URL Admin only (disabled plugin in URL Admin "http://xxxxxx/wp-admin/" & "http://xxxxxx/wp-admin" also disabled in Global Plugins).
Look forward you reply and thanks.