Search Content Sources

In SharePoint 2013,

Is it possible to create additional Content Sources for host-named site collections?

Typically, SharePoint only has the root web app under Local SharePoint sites - 

https://sp.companyname.com

I'm trying to create additional Content Sources to distribute crawling schedules i.e. 

Content Source 1

https://portal.companyname.com/sites/sc1

Content Source 2 

https://collab.companyname.com/sites/sc2

https://collab.companyname.com/sites/sc3

Unfortunately, doing this setup results into the following warning: 

"This URL is part of a host header SharePoint deployment and the search application is not configured to crawl individual host header sites. This will be crawled as a part of the host header Web application if configured as a start address."