[gwbas1c]

Not sure if this will help, but you can try something like:

1: Make an email inbox just for the job opening.

2: Make a silly rule that the applicant must have a specific word in the title. It could even be random characters. For example, you could state "To apply, email applications to [e-mail] with 'ghubv' in the subject."

Then, make a rule that forwards emails with that specific word to your real email box and ignore the rest.