bypass rear coolant lines?

The rear coolant lines that feed the rear heater on my 2001 GC are leaking. The mechanic wants $1000. to replace them (ouch!).
Can I simply bypass them somehow? Should I plug them or cut and reconnect them at the firewall? Any advice greatly appreciated.
Will

cut at firewall and connect together with heater hose and 2 screw clamps. Do not plug them.

On which side of firewall should they be cut?

will123,

I think the easiest way to bypass is by joining the two pipes underneath the car with heater hose and two clamps.

If I am not mistaken the two pipes run side by side to the rear heater core. I have done this in the past with GM powersteering cooliing lines.

Look at where the corrosion stars on the oprigianl pipes, cut off here it begins and join with heater hose. Saves you gettin up in the firewall.