create screlate link to a customize file


I had new file (table) customfile, within this file it had a field which contain the request record id (number).
had a button in request record which will open the logging form for the customfile. Do like to seek advice is there a way to create something like the oob screlate link, so that the management of the field mapping when creating a new record to customfile is manage within this link?

I was able to sync the data over via JS scripting but I do like to make it manageable for the administrator, so that for any addition field to required to be map can be easily done within the screlate link record.