Two men pleaded not guilty to assaulting the owner and several employees of an auto shop in North Reading.Brendan Donovan, 21, of Stoneham, and Anthony Leonard Ferratusco, 21, of Saugus, were arrested Wednesday on multiple charges including assault and battery with a dangerous weapon and armed assault with intent to murder.Police say the two suspects were involved in a personal conflict with a 19-year-old employee of an auto repair shop on Main Street.The suspects allegedly rushed into the shop at 2:20 p.m. Wednesday and beat the victim along with the owner of the shop and a second employee with a hammer and crowbar before they fled.The victims sustained cuts, swelling and bruises, and were treated at the scene.Both suspects are being held without bail pending a dangerousness hearing on Dec. 4.