This is a problem best solved in a structural analysis software. Dynamo’s primary focus is geometry and trying to solve this problem from a purely geometric aspect, would be a very extensive task. There would be a lot of edge cases that you’d have to address and your Revit model would have to be modeled to perfection.
Not saying that the task is impossible but I highly doubt that Dynamo’s the best way to approach this.
Here’s brief example to get you started. I’m using the analytical model because it has a higher tolerance to common modeling mistakes. The below example works only because my model is very simple and completely symmetrical:
A more complicated solution would have to involve walls as well, it would need to figure out exactly what portion of each slab surface area goes towards each support, etc.