3R aims to balance the populations at both schools at roughly 1,100 each by 2012.
Some parents are outraged over the situation.
"This is one in a series of events where, South Ardmore in particular, is being asked to sacrifice," said parent Margo Borell.
That history has prompted demonstrations as the school board fashioned this new redistricting plan.
"They've taken a little square of the only significant African-American community in Lower Merion Township, and a socio-economically diverse community, in the name of some sort of artifical diversity," said Kate Galer of Ardmore.
"We are a working class neighborhood, and I feel the board looks at us as, we're the path of least resistance," said Aaron Williams of South Ardmore.
Now that the school board has passed plan 3R, implementation will begin in the fall semester.
Some of the dissenting parents are considering a court fight to try to block it.