While such functionality is supported by SFTP protocol, I'm not aware of any server actually implementing it. So even if it is added to WinSCP it would not work.

I would like to control access to a file concurrently from two users. Access in the sense that when winscp after login shows the dirs and files of the remote computer one can double click a file, edit it locally and let winscp upload it back automatically. I want to know if winscp already has a function where it prevents one user from accessing it while another user is editing it.
Thanks in advance,
Ines