You can't do exactly what you want since the show/hide patterns are static and don't have any way to tell which is the highest number for any group of files.
If you create the different file versions within Opus then it would be easy to modify that step so that it includes a pattern which Opus can ignore when creating a backup of the current file. When I want to create a snapshot/backup of a file in Opus I use a button which adds the current date and time to its filename. You could make a similar button which copies the selected file, putting the date/time and a special string (e.g. "snapshot") into the new file, then filter out files matching that pattern so that only the current version is still visible.
Of course, if you are creating the different files by saving them in another program, manually increasing the filename's number when you do so, then this won't work as well. You could still rename the files using a button in Opus but you'd have to manually select them each time, which would be a pain.
Actually, you could make it a one-click operation in Opus by writing a clever VBScript rename script, I guess. The script could look at the directory and rename all but the highest-numbered files of each group so that they contained a string that made Opus hide them.