Overlaping surfaces for galapagos

Hi guys!

Im quite new with grasshopper and maybe you can help with one problem I have. I have three rectangles whose positions will be the genes for galapagos. The problem I have is that I dont know how to do it for the rectangle surfaces not to overlap between them. Any idea? Sorry if its very simple or totally wrong... I am starting with grasshopper and with the blog. 

Thank you so much for your help!