Selecting Dynamic file directory for sender communication channel

Hi Experts,

We have a requirement like below:

1. Scenario is a File to IDOC (3rd party FTP to SAP)

2.Order Files will be placed in the different folders, these folders are based on the GLN value.

    Suppose if the GLN is "9999" then the files will be a placed in directory "/9999/ORDERS/" in the 3rd party FTP.

    Every time a new file is created the path get differs

3. Requirement is every time ORDER file is created at 3rd party then the files will be placed in the respective GLN folder path and the PO system has to pick up the files from the directory dynamically.

Now, How to configure the file sender communication channel to get the above the requirement satisfied

Thanks in Advance, for your suggestions