Define and separate traffic by Policy

Hi,

I will try and explain this as best as possible.....

RADIUS --> SRX1(Radius-VR) --> SRX1(Customer-VR) --> CORE --> LNS --> LAC --> CPE

The RADIUS could also access the internet via the core and the upstream provider. 

So, the policies between the Customer-VR and the Radius-VR are working exactly as I want them to. This means PPP authentication requests from the LNS to the RADIUS.

However, I have just been asked if I can allow Internet access from the Radius for repo updates. This will be via a separate route if it's possible.

Is there a way, on the SRX, that I can tell UDP ports 1812, 1813 and 1814 to go to the LNS while allowing the repository traffic to go via the core and upstream providers? Or will I have to perfform this action on the core itself?

Thanks