I'm making NPCs to inhabit a campaign I'm working on, and the standard soldiers are level 3 Fighter (Phalanx Specialist) With Longspears and Tower Shields. I'm planning on giving them the Shake it Off and Shield Wall feats to make them more resilient.
My concept for the army is that the front rank of soldiers use their tower shields for total cover while the second rank attack, meanwhile archers shoot over their heads and cavalry hit the stalled opposing army in the flank.
My question is this: would it be justifiable to give the phalanx, being a virtual wall of tower shields, either a bonus to reflex saves, evasion, or some other boon vs. blast spells like fireball?
Apart from a battle herald or feats like iron will to boost saves or dedicated counter-spellers, are there any other ways to provide mass defense against AoE spells?