Forte : How to showcase / link index images to other pages

Site URL: https://tomato-emu-8lxb.squarespace.com/

Hi - I am using the Forte template for an architectural portfolio and so am housing multiple project galleries in separate indexes -- using indexes to create categories (ie. residential, commercial, etc). I would like the homepage index to pull from multiple projects  outside of that index -- but it seems for the homepage I have to create one index and the pages can't link outside of that index. If I do this I can not organize/cagtegorize the projects .... is there a way to tell index images to link elsewhere? 
 

I think it will make sense if you look at the site... thanks for any help.