Install Concrete 5 on same database of other CMS installation

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I'm a web designer who work with Joomla and Wordpress. I found Concrete 5 that may be a parallel, or something like, opportunity so i decided to install it on my development site. I have just a DB, and I'm use to install every demo site inside a subsite like demo1.mainsite demo2.mainsite etc. so I can share the development of the sites with my customers. To do that I install every instance of joomla/wordpress with a different DB suffix something like xxxdemo1_, xxxdemo2_ and so on.
I started to install concrete 5 with the same idea, but in the second page there is no option about any suffix for the db.
I tried to found something around but nothing in the documentation say something.
Have you any suggestion about it?
Thank you for any help you may provide

trazdum