title: Effective solution to map names with groups
body: <p>I have some staff names. Each staff can be in different groups. Say staff names are N1, N2, and N3, and group names are G1, and G2. </p>
  
  <p>I need to show in a webpage which staff belongs which group (sorting by groups). E.g. G1 contains N1 and N2. </p>
  
  <p>Also I need to show (when another button is clicked) for each staff what are the groups they belongs to. E.g. N1 belongs to G1 and G2.</p>
  
  <p>What is the effective way to do this in a webpage?</p>