Is it possible for specific extensions to use specified parking lots? For example, extension 100 can ONLY use parking lots 5901 to 5929; extensions 101, 5930 to 5959; and extensions 103, 5960 to 5999.
You can easily do it by modifying the park dialplan and adding a ${sip_from user} condition to check for the extensions and modifying the destination_number condition for the park extensions you want. Copy the dialplan and set it for every group of extensions.