sorry, maybe i should have said  <smart-list-item-group> instead.
https://www.htmlelements.com/demos/combobox/item-template/
is it possible to use a dataSource with a <smart-list-item-group>?
in other words, the car example combines “smart-list-items-group” with “smart-list-item”:

<smart-list-items-group label="Swedish Cars">
<smart-list-item value="volvo">Volvo</smart-list-item>
<smart-list-item value="saab">Saab</smart-list-item>
<smart-list-item value="saab">Scania</smart-list-item>
</smart-list-items-group>

is it possible to do something identical using a dataSource?