Multiple Surfaces Displayed in Cross Sections

Can you check in the surface file to see if there are three surfaces in it : merged surface and 2 others surfaces that you used to merge?  If yes, you can either remove the rule on the merged surface or deactivate it.  Then delete the other two surfaces in the file.  The reason for doing this is to keep the merged surface from linking to the deleted surfaces.  
The best solution to create the merged surface is to have both of your surfaces in separate files which you can reference into your file that you use to create the merged surface.  This way every time you update either or both surfaces, the merged surface will be automatically updated as well.  Additionally, when cutting the cross sections, you only need to reference the merged surface file into the container file and dont have to worry about the other two surfaces showing up in your cross sections.  

Can you check in the surface file to see if there are three surfaces in it : merged surface and 2 others surfaces that you used to merge?  If yes, you can either remove the rule on the merged surface or deactivate it.  Then delete the other two surfaces in the file.  The reason for doing this is to keep the merged surface from linking to the deleted surfaces.  
The best solution to create the merged surface is to have both of your surfaces in separate files which you can reference into your file that you use to create the merged surface.  This way every time you update either or both surfaces, the merged surface will be automatically updated as well.  Additionally, when cutting the cross sections, you only need to reference the merged surface file into the container file and dont have to worry about the other two surfaces showing up in your cross sections.  

Thanks for your help! After deactivating the rule, I deleted the original surfaces from my merged file so only the merged surface remained. This solved my problem. From now on when merging surfaces I'll make sure all surfaces are in separate files.