There was no problem with 2 sisters/brothers marriying another 2
sisters/brothers , in the way David Edelman describes.
in fact my GGmother -GGfather were the same:
My Ggmother Yanka WEISZBERGER ( born 1870) married Jakab CZIESLER ( born 1866)
while his brother Ferenc CZIESLER maried her sister Rozsa WEISZBERGER ( born 1879)
This all happend in Austro-Hungarian empire.
I don't know of any Jewish low against it , and it seems logical in the
conditions David described. Don't forget that if the families were very
religious it often happene that the marrige was arranged.
And what is better then a family we already know?