Inter brain synchrony (IBS) has been observed in many social interactions. IBS has been observed between people in:  heart beat, music performance and listening, brain waves, video gamers, movie watching, duetting pianists, team collaboration,  team work with two aircraft pilots, child-mother relationship and other activities people do together. In most cases researches have observed the IBS behavior by using fMRI or EEG.

Inter-Brain Synchronization during Social Interaction  https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2923151/  

The Brains of people playing online video games synchronize, even when there is a physical distance between the players.    https://neurosciencenews.com/brain-sync-distance-21330/.