Accessible Document Structure in Articles Window, from Primary Text flow?

Without having every paragraph element in its own text container, how do I structure the document in articles for tagged export?

<part>
    <h1>
    <section>
        <h2>
        <text>
        <text>
        <text>
    </section>
    <section>
        <h2>
        <text>
        <text>
        <section>
            <h3>
            <text>
            <text>
        </section>
        <section>
            <h3>
            <text>
            <text>
        </section>
    </section>
</part>