Not sure if this is normal, but our Architect plans simply show the steel locations and T joint. The structural calcs then specify the size of the steels. None of the drawings are detailed 3D diagrams of how the steels will join together. I had assumed this was normal, implied, and worked out by the builder?
Anyway, had a chat with them and the plan is to re-hang the joists on to the new 'blue' beam that will be hidden in the ceiling. Sounds like a lot of work (including re-routing of some pipes), but that on them. However, will result in all beams being hidden in the finished room.
Suppose it was an oversight on my part to not drill in to this detail before starting, but its one of those "you dont know what you dont know" scenarios.