No I dont think Radmin has this type of ability, but then, why would it, it's a remote administration software, not inventory or asset tracking software. A simple script set to run at startup through group policy can keep track of who is logging into what PC's. We have one set up to create a text file with users login name and PC name in the filename. The file itself contains the contents of a DIR of C:\ just for other torubleshooting purposes, or to see if certain files that are supposed to be there are there.
The files are written to a folder accessable by anyone in IT, and actually by anyone in the company (so if anyone in the IT dept is sitting at a users workstation and needs to access this information, they do not need to log off and log in as themselves).