You load two subfiles the same way you load one subfile except you will have two loops to write the subfile record formats instead of just one loop. And if you want to load three subfiles, you will code three loops, one loop for each subfile record format. If you want to load four subfiles, code four loops.
Loading multiple subfiles is easy.
The tricky part might involve getting them all to <b>display</b> correctly. Displaying a subfile is separate from loading a subfile.