If you wouldn’t mind having a small hashtag annotation following each of the multi-line options, I have a solution.
The key would be to put something like this on the form question:
Then create 3 tags, each of which matches the text following the # (i.e. you can put whatever text you want, just so long as there is a matching tag (and it doesn’t have to be in parentheses) - what I’m showing is just an example).
Then create a Hashtag Automation workflow for the project.
What that will do is, when a new form submission creates a new task, the Hashtag Automation will attach tags to the task for each option that the user checked.
Lastly, create one rule for each option, like this (using my example):
If the task is associated with tag
dv, then create subtasks from the XYZ template.
That should get you what you want.
Let me know if any of the above is unclear or if you have any further questions!