How to retrieve the local files on server side with file name from front pages?

Hi everyone,

I currently encountered a problem. I have a form where users can select several file names among a lot of names, then we'll lead users to another application page with the selected name(s). Since this redirection does not reflect a process or a task at backend( the pool), I have no way to do some operations( like retrieving the files in my repository by names via Groovy) to manage the documents variable, which means I can't display the files by document_ref in my file viewer.

So is there any method that can help me to realize that?