NESTING : partition a list / there are a lot of little lists of number which are sorted in ascending order

I'd like to partition a list.

I have a serie of surfaces I'd like to store in a rectangle.

The pieces are sorted in ascending order and I have made a modulus with the x dimension of my rectangle, but I'd like to partition the list I obtain after the modulus :

I need grasshopper to see how much pieces can enter in the x longer of my rectangle:

take a look at the screenshot

Any idea ?