Okay, got it. I have been able to use a nested loop, modifying my data structure to:
$VAR1 = [
{
'inner_loop' => [
{
'data' => 'one'
},
{
'data' => 'two'
},
{
'data' => 'three'
}
]
},
{
'inner_loop' => [
{
'data' => 'four'
},
{
'data' => 'five'
},
{
'data' => 'six'
}
]
},
{
'inner_loop' => [
{
'data' => 'seven'
},
{
'data' => 'eight'
},
{
'data' => 'nine'
}
]
}
];
And the following template
<tbody>
<TMPL_LOOP NAME=DICTIONARY>
<tr>
<TMPL_LOOP NAME=inner_loop>
<td><TMPL_VAR NAME=data></td>
</TMPL_LOOP>
</tr>
</TMPL_LOOP>
</tbody>