JSFiddle - React, Tailwind, and code Playground

HTML

<p id="1"></p>
<p id="2"></p>
<p id="3"></p>
<p id="4"></p>
<p id="5"></p>
<a id="first" href="">Color First Group</a><br />
<a id="second" href="">Color Second Group</a>

CSS

p {
    height: 25px;
    width: 25px;
    background: #FFFF00;
    margin: 2px;
}

JavaScript

var one   = $("#1");
var two   = $("#2");
var three = $("#3");
var four  = $("#4");
var five  = $("#5");

var groupOne = one.add(two).add(three).add(four);
var groupTwo = groupOne.add(five);

$('#first').click(function(e){
    e.preventDefault();
    groupOne.css({'background': '#00FF00'});
});

$('#second').click(function(e){
    e.preventDefault();
    groupTwo.css({'background': '#FF0000'});
});