Master Key Suite
Grand master key suites are an extension of master key suites and allow doors to be grouped and sub-grouped. Each door is opened by its own key and the grand master and sub master key. Not its group key.
These type of systems are useful in hotels, where each room has its own key.a cleaner may have a key that opens all doors on that particular floor , but themanager would have one key that opens all doors.
Keyed alike groups and common cylinders can be incorporated into this type of scheme.