IRQ conflicts

We have out ethernet eth0 using IRQ 169.
We have another E1 card which through
which we connect to another machine.
This card also has a driver (written locally).
It appears also to use IRQ 169 also, so
interrupts to 169 are getting confused.

When I stop everything using the E1 driver and
rmmod or "modprobe -r" the driver, I get
"interrupt for IRQ 169 disabled" which then also
screws up our internet connection.

Does anyone have an idea how to solve this?
Use different IRQs?  I notcied a
pci=irqmask=MASK option, but cannot figure
out how to calculate the MASK, and I have no idea if
this would help anyway.

Anybody know a way to force a different IRQ?
(There are not too many slots to physically change
the hardware to).


Thanks