You can easily have a technical solution by scheduling the boys and girls schools to start the school day half an hour (or however long) apart so that it is impractical to have the boys schools students picked up at the same time as the girls schools students.
It seems that it doesn’t work that way. The monitor can say what times busing will be provided and the schools will have to work around that. (Watch the youtube video titled “BOE State Monitor Announces Coed Busing for 2015 2016” )