Create an affinity group.  Go to add a server or agent to it.  The page's breadcrumbs is this:

JON Administration  >  Affinity Groups  >  Affinity Group Details  >  Affinity Group Servers

or

JON Administration  >  Affinity Groups  >  Affinity Group Details  >  Affinity Group Agents

There is nothing in the breadcrumbs or at the top of the page that actually tell me which affinity group I'm adding these two.  We need to put the name in here somewhere so the user knows which group they are adding to.