Is it possible make a question required when previous question "long Text" contains anything?

Hey everyone, 

this is a somewhat unusual case, but it would be pretty important to us.

We collect feedback with typeform after we consult our website visitors.

The survey has 3 multiple choice questions, 1 long text question and 1 email question.

Whenever we get a long text back, ideally we would like to contact that user again.

At the moment, whenever the long text is filled in, the email is not required in the next question so we cannot contact the user afterwards. 

I assume it is not possible, but I am still asking: Is there a way to make question 5 “required” if question 4 contains anything at all.

I thought of having two different email questions and show “required” or “not required” based on the answer of question 4. However, I don’t know how this would be possible either.

I would need a logic option like: If 4 contains “any answer” or “isn’t empty” jump to question X.

Any advice is appreciated.