That sounds like a dificult task. I know that Sony’s sound Forge does batch conversions but it will still need to know which to merge with what. If you have all the combinations in excel or something you might be in luck as you can write scripts for Sound forge.
Will any of the parts need balcancing or are all of them the right volume to mix with all the other combinations?
website: https://www.whitebeetle.com
rss feed: https://www.whitebeetle.com/rss.php
blog: https://whitebeetle.blogspot.com
other website: https://www.johnmilner.co.uk