title: Observable from more than one BehaviorRelay RxSwift
body: <p>I am trying to achieve a subscription of 3 different BehaviorRelay using RxSwift. The idea is following:</p>
  
  <pre><code>let disposeBag = DisposeBag()
  
  class ClassA{
  
      var br1 = BehaviorRelay(value: "BR1_1")
      var br2 = BehaviorRelay(value: "BR2_1")
      var br3 = BehaviorRelay(value: "BR3_1")
  
      /* Some other variables */
  
  }
  let classA = ClassA()
  
  
  class ClassB:CustomStringConvertible{
      let classA:ClassA
  
      var description: String{
          return "\(br1.value), \(br2.value), \(br3.value)"
      }
  
      var br1:BehaviorRelay&lt;String&gt;{
          return classA.br1
      }
      var br2:BehaviorRelay&lt;String&gt;{
          return classA.br2
      }
      var br3:BehaviorRelay&lt;String&gt;{
          return classA.br3
      }
  
      init(classA:ClassA) {
          self.classA = classA
      }
  
  }
  let classB = ClassB(classA: classA)
  
  classB.br1.asObservable().subscribe { (value) in
      print(value)
  }
  
  classA.br1.accept("BR1_2")
  </code></pre>
  
  <p>It prints:</p>
  
  <pre><code>next(BR1_1)
  next(BR1_2)
  </code></pre>
  
  <p>By doing that I am "populating" my ClassB with objects from ClassA and by setting a subscription to the objects in ClassB i can react to the next events.</p>
  
  <p>However, I would like to create a function such as:</p>
  
  <pre><code>func reactingFunction(br1:BehaviorRelay&lt;String&gt;, br2:BehaviorRelay&lt;String&gt;, br3:BehaviorRelay&lt;String&gt;){
      /**/
  }
  </code></pre>
  
  <p>to be called every time any of the br produces onNext event. Can I create a mix subscription for all of them?</p>
  
  <p>Thank you</p>