“Medrashim are full with the account that the Jews had no problem whatsoever, even when both were drinking from the same source.”
LF, the earliest source for this is the Yalkut Me’am Lo’ez, written about 500 years ago. There is no Midrashic account of the famous “two straws, one glass, Jew-gets-water-Mitzri-gets-blood” which has been the inspiration for the ubiquitous kindergarten project seen this time of year. It is unknown if the YML said it mi’Sevara, or if he somehow had some source that we do not.