Static routes

Hopefully somone can help me.

I have a PC with 2 NICs. 1 NIC is connected to the Internal network
and the other NIC is connected to a Cable Modem, which provides a
faster internet connection.

I can confirm that my PC is using Internet traffic through the cable
modem, which is what I want.

Unless connected to the Cable Modem, the device is unreachable.

My question is this. Is it possible for my colleagues to setup a
static route to my PC and then access the cable connection, without
physically being connected to the cable modem via a network cable?
I thought this could be done by setting up a static route to my PC,
but I am not having much luck with this so far.

The network looks like this:


Cable Modem Internal Gateway
------------------------------------ Internal LAN Switch
192.168.1.1
10.10.10.1 /
\

\ /
\

\ /
\

\ /
\

\ /
\
Multihomed PC
---------------------------------------------------------------------------
Network PC

10.10.10.2
10.10.10.3
192.168.1.2

Thanks in advance for your help.