If you are using FileMaker 12 or newer, see if setting up the container field to use "external storage" will work for you. It allows you to insert a copy of the file and then FileMaker transfers that copy to the external storage location. FileMaker manages access to the file so you don't have to map/mount to the file's location on each client computer.
If you are using an older version of FileMaker or other considerations require that you not use external storage, there are two different tricks that you can work with, either separately or in combination to get this to work:
On the layout where users insert new files, a script--perhaps performed by OnObjectModify on the container field, can extract the file path in the container field, compute the "fully qualified file path" that connects to the same file, set a $Path variable to it and can then re-insert the file from that location.
A calculation field can have "container" as the result type. This calculation field can take the file path info from a container field and compute a different file path--such as using the J: drive letter instead of K: or by computing the fully qualified path to the file. You can't insert a file into such a calculation field, but you can use it to display the file.
For more on $Path variables, the file path info inside "by reference" container fields and the script steps that can use this info, see: Exploring the use of a $Path Variable in Scripts
Using your advice I was able to make it work. Here's how I set it up:
-Users initiate a script to add a PDF file reference
-Open file dialog takes them to the networked virtual drive
-PDF reference inserted into container
-Based on GetAsText(container), a calc field re-formats the reference syntax to "point" to the fully qualified domain instead of the virtual drive
-Insert PDF (reference; "$Path")
Does this seem ideal to you? I feel like I could simplify it somehow.
The only thing that I see that could be simplified is that you probably don't need GetAsText (container) as you can usually refer directly to the container field to access the text of the file reference.
thanks again, i'll give that a shot