VisualCron 11.2.3

Basically, i have an SFTP task that downloads files from one of our vendors at the hospital. I can not delete files from that remote server once i download files to our network folder. Then when i try to grab new files only the task errors out, I assume because some of the files already exist in the folder. I cannot simply pull by modified date as jt could lead to other issues. I just want to grab files that do not currently exist in the destination folder. Is there a way to do this?