This means that Joseph, the brothers, and the other Egyptians are eating in three different places within the same room. AT: "The servants served Joseph by himself and the brothers by themselves and the Egyptians, who were eating with him, by themselves"
This can be translated as a new sentence: "They did this because the Egyptians thought it was shameful to eat with the Hebrews"
# could not eat bread
Here "bread" stands for food in general. (See: [[rc://en/ta/man/translate/figs-synecdoche]])
# The brothers sat before him
It is implied that Joseph had arranged where each brother would sit. You can make clear the implied information. AT: "The brothers sat across from the man, according to how he arranged their places" (See: [[rc://en/ta/man/translate/figs-explicit]])
# the firstborn according to his birthright, and the youngest according to his youth
The "firstborn" and the "youngest" are used together to mean all the brothers were sitting in order according to their age. (See: [[rc://en/ta/man/translate/figs-merism]])
# The men were astonished together
"The men were very surprised when they realized this"
# But Benjamin's portion was five times as much as any of his brothers