COROS pairs with Stryd by an ANT+ connection, and it is possible to have several pods added to the Accessories list of one COROS watch. The watch will automatically determine which pod in the added list is with you on your run and record the data from that particular device.
Pairing two Stryds to one watch is not very useful. We instead only recommend that you pair one Stryd to your watch. You can collect running data with a second Stryd and then syn the data to your account after the run is over.
NOTE: a limitation of the COROS watch connection to multiple Stryd is the settings that are used for each device. Settings like where to record the distance from ("use STRYD" versus "use GPS"), calibration factor, and Critical Power cannot be independently set for different Stryd pods in the COROS accessories list. This means changing the calibration factor for one pod in the COROS Accessories added list will update the calibration factor to the same value for all other Stryd pods in the added list.