How to make a table row expand and fill remaining height while preserving rowspan cells?

<style>    table, td {        border: 1px solid #000;        border-collapse: collapse;    }    tr:not(:last-child) {        height: 0;    }    tr:last-child {        height: 100%;    }</style><table><tr><td>Group 1</td><td rowspan="999"><div style="height: 300px; width: 20px; background: #000;"></div></td><td>Group 1</td></tr><tr><td rowspan="2">Group 2</td><td>Group 2</td></tr><tr><td>Group 2</td></tr><tr><td>Group 3</td><td>Group 3</td></tr></table>