Any easy way of searching for possible itineraries?

I'm primarily interested in US - China - TPE or TPE - China - US. I'm okay with a bunch of layovers in random places in the interim.
For example if I pick PVG/PEK there are direct flights to TPE/TSA so that's not that hard, and there are a bunch of flights from PVG/PEK to the US.
But if I pick something like CTU then lots of the options have layovers in another Chinese city so that's not possible. I can manually exclude layover cities in Google Flights I guess? On the flip side, if I pick a direct flight from PVG to TPE, I can't fly US-layover TPE-PVG either, so have to exclude those itineraries too.

Side note, having Chengdu and Chongqing on two separate TWOV areas is annoying.