StitchArtist allows the display of all hoops in the platform, including multi-position hoops. The multi-position hoops are not there to automatically split. Their inclusion is for the purpose of creating designs specifically for those hoops. As you are in control of all stitch objects, you decide what parts of your design will go in each hoop section.
We suggest creating a separate design for each hoop section. If the hoop you are using is not a physical multi-position hoop, you will need to add alignment lines that exist on each design so that the position of the designs can be lined up by the embroiderer when sewing.
As each design will center when it is saved, we suggest using a basting box for each hoop position. The box should be centered in the hoop section, and should completely contain your design section.
Once you have each design created, copy them to a separate design page and save them individually. As this is an advanced topic, you may want to look online for specific instruction.