Using Insert routing mode, it is possible to use H90 like a mixer by connecting one signal to In 1 and another to In 3. Create Insert 1 and set its Mix parameter to 100%. Create a parallel routing and place the insert before Preset B. This will allow you to process In 1 through Preset A and In 3 through Preset B and mix both signals to one output. Here’s a video explaining how to do this: https://youtu.be/0G_WtfUatSc?t=1190&si=gPg_1S3b1oW-nJPv
