In that case, you should use Create->Via and then select "Stack" and you can enter the start and stop layers. It will create a stack of vias. Yes, it's multiple via objects, each of which is between a pair of layers, but this has the advantage of being simpler, and also better understood by multiple tools.
If you use create wire, and change through multiple layers (e.g. hit the space bar to change layer), it will place a stack of vias for you.
Also, in the "Options" toolbar there is an icon to control whether Via Stack selection is on or not (this also appears on the Options->Selection form). What this does is ensure that if you click on a stack of vias, it selects the entire stack, rather than just the individial vias.
So there really is no need (and indeed it's not recommended) to create specific stacked vias in the tech file.