Here's a visual of how Los Gatos's public elementary schools feed into the middle schools, and then how the middle schools feed into the high schools.
The width of each stripe is roughly proportional to how many kids transition from one school to another in a given year. It's far from perfect and based on some dirty data, but should give you an idea of the relative number of kids transitioning to each school within a year.
In most cases, the size of a school's bars indicates its relative enrollment. But the bars for Rolling Hills Middle, Union Middle, Leigh High, and Westmont High are too small because these schools are also fed by schools not shown on this chart. The missing feeder schools are in Campbell, San Jose, and Saratoga and do not serve students with Los Gatos addresses.
(BTW, I used the Sankey Diagram in Google Charts to create the above chart).