This may appear to be a daft question to some of you specialist, but why do we have main tank and a co-located split supply tank? Why not have a split main tank with gaps in the baffle feeding the engines?
Presumably because as the aircraft attitude changes, some parts of the main tank will be left dry. The engine feed tanks are kept full, thus giving a constant head of fuel supplying the engine and a considerable time delay between change of aircraft attitude and loss of fuel pickup. A feed tank could be thought of as a glorified float chamber on a carburettor.
Whilst it would be possible to have one tank feeding both engines directly, compromises would have to be made to the shape of the tank and the shape of the helicopter to get a reliable supply.