Name the bias when one attributes all group successes to the individual they're in contact with the most

Question

This is the fallacy when one assumes that all successful outcomes were most likely thanks to that one individual that they always communicate with, and fail to recognize (consciously or subconsciously) the effort of the rest of the group, or an individual from that group.

I am not sure if this is a proximity induced issue, continuing communication, perceived availability, or some sort of quasi in-group bias.