Yes, but they are prats, they never use their pikes, only swords, worst unit in game.
Keep them in guard mode, pike formation and instead of attacking the unit click the area behind them. The pikemen will mow down those bastards without having the problem you proposed.
Billmen are the worst unit in the game. Utterly pointless.
Fear not, crusader, Prester John will save you from the wrath of the Devil.