If you want to link certain words or phrases to one other hub of the same type or same topic you can use the link and unlink tool inside the text module.
When working with text highlight the word or phrase you want to link. Then with the highlighting still visible click on the small icon that looks like a link in a chain. When it opens put the url of the desired linked hub in the proper box, close and then you are finished. The other chain link icon, you may notice, is like a broken link. That is what you click to unlink if you make an error.
LInking common hubs to each other is also done with tag rss feed entries using the rss module. you can find threads in the forums about linking in that manner.