To sync 2 ZL Pandora’s together both have to be the same size. There is no electronics involved but rather aligning the hoops together to begin in the same spot.
The quick way is to perform a hard reset on both hoops first to make sure that the color wheels slots are the same, if no color wheels slots have been changed than soft reset.
This will bring you into Home Mode and defaults are set in place. Then setup each hoop separately for Pattern Groups, Colors and Shuffle Modes.
Once both hoops are setup the same put one on top of the other and use the numeric keypad to start both hoops at the same time.