title: Angular 5: How can I iterate over form components and set value
body: <p>I have an Angular 5 form (<a href="https://ng-bootstrap.github.io" rel="nofollow noreferrer">uses Angular Bootstrap 4</a>) radio button group components. There are about 25 radio button groups each has 3 options: N/A, Secondary, Primary. I would like to allow N/A and Secondary for all radio button groups however only one radio button group may have Primary checked.</p>
  
  <p>I'd like to have a click handler that intercepts any Primary check, iterates over all other radio button groups and sets them to Secondary if currently checked as Primary thereby leaving only on radio button group with a Primary option checked. How is this possible from within my click handler?</p>
  
  <p><a href="https://i.stack.imgur.com/oCOPL.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/oCOPL.png" alt="enter image description here"></a></p>