Many organizations use PRINCE2 at their project management level. Introducing RUP means introducing an overlay in process description.
At the website of IBM, the following interesting (and practical) whitepaper became available.
Introducing the loose coupling allows for the current organization to keep working the way it used to be (that is, at management level) and still create a process at the Software Development Level that will improve the success rate of IT Projects.
You will find the article here.