title: Dynamically select property to observe with RAC
body: <p>I have a lot of UISegmentedControls (74 actually) in one view that I want to two-way bind with their respective model properties using RACChannel. To reduce the code, I want to assign these bindings at runtime using enumeration of an IBOutletCollection.</p>
  
  <p>In order to make this work, I have to come up with a way to select the correct property dynamically. I have 74 properties on my model that follows this naming convention: "item1a, item1b, item1c, item2a...".</p>
  
  <p>On every UISegmentedControl I have an attribute, "name", that I can extract at runtime to know which control should be bound to which property.</p>
  
  <p>What I would like to do is essentially</p>
  
  <pre><code>RACCHannelTerminal *modelTerminal = RACChannelTo(self, "DYNAMIC PROPERTY NAME");
  </code></pre>
  
  <p>I can get the value for a dynamic property name by</p>
  
  <pre><code>[self valueForKey:@"item1a"];
  </code></pre>
  
  <p>but this doesn't give the the actual property to observe, just a value.</p>
  
  <p>Is there any way of doing what is described?</p>