Munatia Plancina - Three Sisters

no romans often named their daughters the same name. eg Julius Caesar had 2 sisters named Julia

Agreed, but Julius Caesar's sisters were at least distinguishable by the suffixes "Major" and "Minor", whereas the three Munatia Plancinas seem to have had identical names. The eldest one, who died before the others were born, may well have been "replaced" by the second one - a practice common until quite recently - but the two younger ones are shown as having been alive contemporaneously and as having died in the same year as each other.

Wikipedia doesn't help much.