allow and block user access

My server: On prem CRM 2013 Service Pack 1 Update Rollup 2

I am trying to block users from viewing accounts owned by other users but allow all users to view accounts owned by one specific user.

So I was able to do the first part using security roles set to "read privilege on account is set to user" but I cannot allow access to that specific user since all is blocked.

Any help will be greatly appreciated.