Search settings in sub sites

I have 4 project sites, every site has few document libraries, I want to search in the current project site first and if I select "everything" or "all projects" it should search in all project sties.

my site structure is as follow

• ali.dev/internal (site collection)


• http://ift.tt/1CRmIwZ (project site which contains all project sites, just a container)


• http://ift.tt/1DyN89D 1 (Actual project site)


• http://ift.tt/1DyN89D 2 (Actual project site)


• http://ift.tt/1DyN89D 3 (Actual project site)


• http://ift.tt/1DyN89D 4 (Actual project site)

On search result page I want to show some custom refiners, should I create a search page in each project site? should I create a search page in the "project" site which is container of all project sites?

DO I need to configure search settings page of every site?

Search center is also configured but I don't want to use that for project search because I will not be able to edit and put my custom refiners.

I have created a project site template and generating other sites through that template, making manual changes after creating a project site will not be possible, we will have 100s of project sites in future.