Can I add a second fuel tank like this?

[cmedsailor]

I would like to add a second smaller plastic diesel tank (around 40-50lt; lots around in chandleries) in a lazarette to be used for transferring fuel in the primary tank rather than using jerry cans.
Is it possible to add a Y connector to the fuel tank vent hose, at some point low near the primary fuel tank, and connect to it a second hose that will go to that smaller tank? I could even add a filter to that hose (not sure what type though), a lever valve and of course some kind of pump (probably that squeeze pump thing since the smaller tank will be above the primary tank) to transfer the diesel from the small tank to the primary one.
Can you see any problems with this? The idea is to simplify the process of using jerry cans to refuel during a long passage.
Thanks

 

[rogerthebodger]

I have a similar arrangement with 2 of my tanks sheering the same vent. My Y connector is close to the higher tank to reduce the possibility of an air lock.

I also have separate fillers which I think are essential.