HELLO...
If I am understanding this right, your beams will go from top of one wall to the other, which you want to know if those cross beams and roof can be pored together..da me from jersey!
Down past with the big cement church, past the old peoples home going to freemont, on the left is a place that makes if I spell this right " bargeta's " that you order, roof beams up to 18 feet.
They are cement poured into steel beams as a form.
They are approx 3" by about 6" by and up to 18 feet long.
There are double re-bar the length and have a rear tri angle set of re bar above the beam.
They are workable by two or three workers.
The are spaced approx 4' a part on top of wall beams. Just laying there they are self supporting, but as it worked upon ya use some cross 2x2 or 4x4 under them.
The foam insulation has groves on the 4' sides that will rest on the " begeta's "
Now, when that is in place, the wall re bar, and grid
re bar and elec and light tubes are placed on the grid, above the insulation.
When cement is pored, every 4' a 6 or 8 inch beam is pored, and the roof cement, at one time.
I had my place done that way, and its so strong the roof is now my second story floor.
This is a newer system them pouring beams and useing plywood for the roof pour, then taking down the expensive plywood.
If ya need more on this newer way, let me know.
I think this is what you were refering to, I hope!