Isolating the signals from individual leads /SHIELD-EKG-EMG

[kakovalipuduk]

Hello, I am trying to better understand how the OLIMEX SHIELD-EKG-EMG works so I can make a makeshift ecg device. But I was curious if it is possible to isolate the limb leads(RA,LA and LL) individually from each electrode so I can calculate aVR, aVF and aVL readings.