We have a Joomla installation on our local server where we host many landing pages and route them with a proxy across different domains for different sub-companies. The goal is to use one single template. But we need different favicons because each domain has its own favicon.
This can be done with the Gantry Framework you would need to make a field in theme settings that will call the favicon and then use that field in overrides to call the different icon the same principal would be like you call the backgrounds.
This would require some php coding but its possible to make!