Translation:I do not know either of the two sisters.
In English, it would be odd to say "none of" when referring to only two people or things.
nessuno/a is usually translated as 'no-one', so it should be 'neither' or 'either' here, depending on how you construct the sentence.
If nessuna is the correct translation of " either " in this sentence then it could not be used to translate " I know none of the three sisters " but I think it could be used, am I right or not ?
While 'the two sisters' is literally correct, one would be more likely to say 'his (or her) two sisiters'