Put the first template as group 1 and the second as group 2. Then you would set your attempts on each one at how many accounts you would want to create on that template. Hopefully, all will pass through and your accounts will get set up. Then when the attempts are all used up, the second group will kick in gear.
You can set this up in the task addition. I'm going to try and put up a vid to show how to do this.