Althon have recently supplied several precast concrete headwalls to Inverness Airport.
This included angled headwalls, splayed headwalls and also 2 No. SFA20B headwalls with 1000 x 500mm Toes.
They were able to cast multiple pipe openings into their headwalls, and being able to cast several openings into one headwall means that you can have more than one pipe discharging out of a single precast headwall unit.
You can use Althon's Headwall Specifier to find the headwall you require. On request they can provide pricing and design drawings for your chosen headwall with more than one pipe opening.
View Precast Concrete Headwalls Product Entry