Possible Clues:

• American and Arabian agent for the most part taking theatre's material on the road
• Comes to get garages refurbished
• American and Arabian agent nearly takes theatre's stuff on the road
• Groups into a class
• Collects together building materials
• Garage gets building concrete materials
• That's all of them with one horse about the barriers
• Garages get in a panic about materials on the road
• Sums up the scrambled egg as great
• What they all come to is a horse about the entrances (10)