Assign Role based on Table Cell value

[Æ •]

I have several users accessing PostgreSQL database managed through pgAdmin. The 
database consists of a table with several columns and rows. I want to grant 
permission to certain users to write/edit certain certain rows based on the 
value of a certain cell i.e., if cell value = x than user 123 has edit rights. 
From what I have understood, the Grant Wizard grants access to the entire 
table. Is there anyway be more granular in granting access/assigning 
roles?Thanks