I’m building a site, which has multiple companies. Most companies can share the exact same template, but some need an extra region on the page, where each company can have their own box, for example with some advertising, or recruitment messages.
I think what I should do is add the “default” content to the company’s section front matter through companies/_index.md.
Then on any given company single template you can use:
<h3>Default Content</h3>
{{ .Parent.Content }}
{{ with .Content }}
<h3> Company's own Content</h3>
{{ . }}
{{ end }}
It should work with your current dir structure even though all you have is the home and then one company. My example work for several companies living under a shared directory.