About the use of parallel geometry

I’ve recently encountered some problems with parallel geometry. I was going to use the command /gps/pos/confine to restrict the gps to the source geometry defined by the parallel geometry that is contained in a model generated by the DICOM example. I registered this parallel geometry in the main() function and set the layered mass geometry switch. However, the program runs and the /gps/pos/confine command does not find the parallel geometry I defined. Have you encountered this problem and do you have any solution?

Now I found a problem, through QT I can see that parallel geometry and mass geometry should be equal in status, so I guess /gps/pos/confine is using the body defined in mass geometry by default. Is there any way to make the /gps/pos/confine command able to see the entities defined in parallel geometry.