RClone on TrueNAS sync file to Google Drive

Hi all, I'm using RClone on TrueNAS to sync a folder on my NAS to Google Drive and I wondered if there's a way to filter out files which are older in the source than the destination, i.e. the file has been modified in Google Drive so I don't want that to be overwritten by the RClone sync.

I've been through the filtering docs (Rclone Filtering) and can't find anything that appears to do this but I'm a bit of a newbie to this so I'm probably missing the obvious option!

Thank you for any support or help you can provide!