@drsnuggles What about using the regex below?

~~~
((0?[0-9]|1[0-1]):[0-5][0-9](am|pm)(-| to )(0?[0-9]|1[0-1]):[0-5][0-9](am|pm))|((0?[0-9]|1[0-9]|2[0-3]):[0-5][0-9](-| to )(0?[0-9]|1[0-9]|2[0-3]):[0-5][0-9])
~~~

I'm not the regex jedi but the regex above should cover:

- 9:00am-5:00pm
- 9:00am to 5:00pm
- 9:00-17:00
- 9:00 to 17:00