Hello,
Yes, you’ll want to use Dual Routing for this setup.
If your guitar first goes to H90 preset A, and then to the IR-D, then your effect from preset A should always be present on the IR-D outputs. Have you tried this setup and are experiencing something else?
The setup should be something like:
Pickup 1 > H90 input 1 > H90 output 1> IR-D > amp and PA
Pickup 2 > H90 input 3 > H90 output 3 > A3 and PA
