Sitemap question

I am currently designing a new global SharePoint that incorporates not only regional sites, but also department areas within each of them. I'm struggling with the development in terms of structure. I've created the site and subsite for each region (EMEA, USA, Hong Kong) but now need to create each with new pages for each department that is relevant to that region, so for EMEA there would be HR, Regulatory Consulting, IT, Marketing, Tax, FRR, etc. but for USA there wouldn't be a Tax area and I can't seem to create the structure that displays each new department page on the left side menu.
Is there a template or sitemap/structure that I can adopt or that is out of the box at all to help?