[RightDeve]

If you click an artillery unit (from the Bombardment unit list), it will jump the Bombardment Map toward the last mission of that artillery unit. Notice the red hexagon outline that indicates the exact place.

So the solution would be:

-Select the FOO
-Open Bombardment Screen and cycle through the list to see which one has the target location (i.e last mission) nearest from that FOO you selected.
-Plot the bombardment.
-Select another FOO and repeat the process.

I assume using multiple FOOs is useful for when they have eyes on target, thus usually the target area is near that FOO. Otherwise, if FOOs are plotting without direct LOS, might as well just use one FOO.