I don’t know yet. The “whohas.arx” doesn’t work quite well anyway. And you have to make sure all the machines in the network have loaded the “whohas.arx”. And, I don’t know how to incorporate this command into LISP.
I found after the computer loaded "whohas.arx" program, you open the *.dwg files which had already opened, you can see the user name and computer name in the dialog. ( I attached.) But it seems difficult to use in Lisp.