MIKROTIK RADIUS - PPPOE BACKUP SERVICE OPTION

We have services that we need to be able to connect to two or more different access routers on our network which is running OSPF. Problem is that when they come online, the access routers advertise that the customer service using the same distance which causes split routing on the customer’s service. We would like to have the option to specify the distance on a service so that when the PPPOE dials up to the backup access router, its on a higher distance.