Hi,
As far as i know, a delivery activity can only use one delivery template for each iteration (in other words you can't have your entire audience connected to one delivery activity, and then generate multiple deliveries from different delivery templates)
You can dynamically change the delivery template that is used by the delivery activity, for each iteration, but as mentioned above, only one delivery template can be used each time.
I would suggest using personalisation blocks or splitting your audience into different subsets and using multiple delivery activities.
Thanks,
Solon