Mikrotik user manager - one compuer per user

Hi,
I am using Mikrotik user manager for my HotSpot. Is it posible to configure restiction on account.
For examle; when one customer buy an voucher and successfully log in, I need that system remeber his MAC adress. In that case, he would not be able to use same voucher on other computer.
Best regards,
Ticho

It is possible to specify MAC-address for the particular user, but I do not see the way how to do it automatically (get from client signup and add to User Manager user information).