I'm currently in the first stages of an ADFS roll-out. It looks like you need to install multiple "federation services" or instances of ADFS if you want to federate with the same party or SaaS application multiple times. Let's say that you have different user populations that use private instances of an application or you have several sandbox environments and a production environment. How are other people handling that?
Let's say I would like to have one instance of ADFS. All of my accounts are in one domain. There is one AD environment. Different sets of users have independent, unique, instances of a SaaS application.
Let's say saasprovider.com/groupa and saasprovider.com/groupb which are mutually exclusive.
Several people have mentioned realms and etity id's to me...please be specific. I can't give them the same metadata document for the second RP trust. I have to have another STS or ADFS instance, right? You can only have one ertity id per federation service installation, right?