Welcome to the Q&A Forum

It sounds like you need a pattern redirect implemented, ideally in one 301. If that's not possible, I would definitely add another to get all the URLs redirected to their new location (avoiding any redirect loop) - better to lose 10-20% of link equity than all! Plus you said the old pages rank well - changing domains already almost guarantees a drop in rankings, even with 301s implemented. You absolutely need the 301redirects! As a last resort, have them 301 to the new location of each page's category. Make sure you test whatever solution you go with on a few pages before pushing across entire categories. Hope this helps!