Load Balancing FTP server

hi

ihave a SAN and there is 10 TB shared Space to the 3 FTP server

i want to load balance the traffic on FTP server

and i want to know is it possible to work this ftp Server ACTIVE/ACTIVE load balancing ?

and if yes if a user open a file on ftp server 1 and at the same time another user open same file on ftp server 2 and they modify that file and save that file what will be happen?does the saved file lost? wich modified section will be lost?

please help if everyone knows