Is It possible to make an email address that will only accept mail received from parties that use a certain subject line?

For example: an email account has been set to only accept mail that has a subject line that starts with **

SUBJECT: long time no see

this is not allowed to be received by you email account.
But - SUBJECT: **long time no see would be received by your email account.

Obviously this is a very simplified example, more complex requiem is desirable.

If this is possible - How?

Any suggestions, answers or advice is hugely appreciated.

Thanks to all respondents.