You can generally choose which Primary School you go to and there is nothing to say that you can't change schools later on if you do need to go to a feeder school. Most Secondary schools are zoned - to find the zones, look for the schools closest to you and then go to the individual school website. They will say if they are zoned or not and then they generally provide a map outlined to zone boundaries.

FWIW - the kids from our kinder went to about 5 different primary schools and the kids from our primary school tend to go to about 12 different secondary schools.