Adding Primission in Smart Sheet (Column Level)

Hello Everyone, Need an assistance to solve one problem. I am trying to implement role based permission on certain columns in the sheet. So for example i have created two Users A and B. What i am trying to achieve is that User A can ONLY VIEW Columns A - B but should have Edit Capabilities for Column C only. Whereas User B can only View Column C only and have no visibility of Columns A-B