While reading old Question: Two birds with one stone? I was reminded of the Russian expression: "A man who chases two rabbits will catch neither."
In English we speak of the futility of "fighting on two fronts". This may have been born from experiences of Twentieth-Century total-war. There was Germany (1914), despite the Schlieffen Plan, fighting on two fronts. A generation later (1944), there was Germany fighting on three fronts.
The Romans, with a huge Empire to police: "local difficulties"; insurrections here; uprisings there; diluting their resources; moving armies; firefighting--how were the inherent difficulties of "chasing two (or more) rabbits" expressed?
A wild guess: "si duos cuniculos persequeris, neutrum capies." =
"If you pursue two rabbits, you will catch neither."