Rabbi Pinchas Ben Yair
From Zissil
Rabbi Pinchas Ben Yair was a 4th generation Tana and was either the father-in-law or the son-in law of Rebbe Shimon bar Yochi.
Association With Rashbi
In the Zohar it refers to him as the Rashbi's father-in-law while in the Talmud he is referred to as his son-in law. It is possible that there were to Tanaim named Rebbe Pinchas Ben Yair one a father-in-law and the other a son-in law of the Rashbi.