I'm trying to set up a few vsftpd instances on a machine that I have no root access to. The authentication should be done through PAM with pam_listfile, like this:

pam_listfile.so item=group sense=allow file=/path/filename onerr=fail

I can ask the administrator to set up a PAM service for me and include that line but he is not willing to create 6 PAM services for my 6 vsftpd instances and I really need different /path/filename set for each vsftpd server.

Is there a way to solve this problem? Can I somehow not use absolute path as the parameter?

(I know the correct solution would be to use one vsftpd instance and set up virtual users properly. However unfortunately I have to work what I have and the users already exist in an Active Directory and are authenticated to the system using another PAM service.)