Yes, but it actually does not really make any difference in licensing if you only enhance some subsection as your intranet section or if you setup additional new web as intranet. It is still a project with different content - in the intranet/ internal membership subsection you practically create a new subweb with different purpose of use (internal data, internal access,content related not only to company presentation but also to company work, processes, daily duties, communication, etc.). Therefore, you need to own another license for that.

Hope it makes sense to you.