You have a few options for integrating Adobe Target to an existing CMS. The first one would be to use a Remote Offer link - you can use Target to return A and return B, but the CMS can say "if we receive A, then do these things, and if we receive B, then these other things" - this can be coded into the CMS, it just comes down to which is more efficient and which involves the resources that you have the most access to. You also have the option of caching it. The benefit of the Remote Offers is that you are not managing content in two places; rather, you are just pointing to a CMS for something that can be delivered to the page. Hope this helps!