{"people": [
        {
            "name": "Sally",
            "group": "A"
        },
        {
            "name": "John",
            "group": "B"
        },
        {
            "name": "Jane",
            "group": "B"
        },
        {
            "name": "Skippy",
            "group": "A"
        }
    ]}

<p>Group A</p>
<ul>
    <li>Sally</li>
    <li>Skippy</li>
</ul>

<p>Group B</p>
<ul>
    <li>John</li>
    <li>Jane</li>
</ul>

<p>Group A</p>
{{#each index.people }}
    {{#is group "A"}}
        {{ name }}: {{ group }}
    {{ /is }}
{{ /each }}

{"groups" : [
    {
        "groupName" : "A",
        "people" : [
            {
                "name" : "Sally"
            },
            {
                "name" : "Skippy"
            }
        ]
    },
    {
        "groupName" : "B",
        "people" : [
            {
                "name" : "John"
            },
            {
                "name" : "Jane"
            }
        ]
    }
]}

{{#each index.groups}}
    <p>Group: {{groupName}}</p>
    <ul>
        {{#each people}}
            <li>{{name}}</li>
        {{/each}}
    </ul>
{{/each}}