I have about 2,500 mainly classical disc rips in my SACD library. I have avoided these ISO issues by extracting them to DSF files. It works just fine. No issues.
http://www.audiocircle.com/index.php?topic=129913.0The software is free. Tags can be saved directly into the DSF media files from the JR library. There are no sidecars involved.
It would take a while to do the extracts, but it can be done overnight as a batch. For me, the extracts take less than 15 minutes per disc with Mch DSF output.
Of course, it might be tricky now that you have a library full of tags pointing to the ISOs. But, I am sure there is a way to convert, though it might be somewhat involved.
You should have listened to Ted_B way back when SACD ripping was getting started. He recommended DSF extracts from the get go specifically from a JRiver tagging standpoint.