Random drawing from 80 entries (16 slots) by using a button

Hi -

I was able to develop a program when you click a button, to select randomly based on name, but the issue that I have. I only want to select up to 16 schools out of 80 and each row, I would like to have a button, where I can click on each row to show up school randomly. I am attaching the file so you can get an idea what I am trying to do. Yes I know one button can do it all, but I would like to select one by one - more interesting that way.

Shannon