How to create a custom special mail-tag?

I’m trying to use the filter “wpcf7_mail_tag_replaced”, witch works but I need in this filter or a better one to get the post_id of the page I’m submitting the form?

The goal is to get a custom meta_key/value in this post where the form is being submitted from, but for that I’m missing the post_id?

Is this the correct filter/hook? If yes how can I accomplished this? Or should I use another one?