Auto export of entries in a group to a different file

Here is how I am trying to use jabref

I have one large .bib file for all my references. When I write a paper I create a new group and add all the references I need to that group. I then select the entire group and “save selected entries as” to create a new smaller bib file in the folder for that paper. This is fine but it takes some time when you are fine-tuning the bibliography. In Zotero there was the option to “Keep external bib file up to date” or something like that so that whenever an entry in a target group changed, the group would be re-exported to the other destination file.

My questions are

  1. Is this a logical workflow for jabref, if not what should I be doing?
  2. If so, is there a builtin ability or plugin which will keep an external file up to date