SMTP for authenicated users who may have blacklisted ip

I have several users that travel with their computers or have DHCP isp setups. I have smtp authenication turned on and usually they send mail without issue. But sometimes, they will have a blacklisted ip assigned to them. Is there anyway to setup the system to ignore blacklists for authenicated users? Basically, I am not as worried about spam tests for authenicated users.