ValueCount ( ContainerField ) will return a value greater than 1 if the file was inserted with the "store a reference" option.
You may find it interesting to define a calculation field set to return text that contains a reference to your container field as its sole calculation term. You can place this field next to your container field and size it to be several rows of text tall in order to see what text may be accessed from within the container field for a given file inserted into it.
Using ValueCount worked. Unfortunately, the files were not stored by reference, which means that there is some other reason that they are not opening on the iPad. Do you have any idea why this would be happening? Unfortunately, I don't curently have access to an iPad, so I won't be able to do much testing until tomorrow when my boss brings his in for me to play with.
That would sound like a question to ask in FM Go Forum.
thanks. you're right. i'll do that