Block Hotspot User's to access Main Router (Coova-Chilli)

[vanrion]

Hi, i have Hotspot using RPi2 and it work well, but i want to block user's from my hotspot to access my Main Router. Telco's in my country prevent subscriber to change the default username and password of the provided router, hotspot user can access my router once they are connected in my hotspot.. Thanks in advance

[allfox]

How about pull out the wire between Pi and the router?