|You would need to interconnect the two routers and give them both IP's within the same subnet.|
LAN IP: 192.168.0.1
Subnet Mask: 255.255.255.0
DHCP Enabled = Yes
Connected to Internet
Router 2 (Airtel):
LAN IP 192.168.0.2
DHCP Enabled = No
Connected to Router 1
Then you could statically assign TCP/IP settings to the one PC you wish to have connect through Router 2 using it's LAN IP as that computer's "default gateway" and "DNS" addresses.
The rest you let get their settings from the DHCP server on their router.
It matters not how straight the gate,
How charged with punishments the scroll,
I am the master of my fate;
I am the captain of my soul.