Matching tags to IPTC metadata

I would like to link (match) tags to attachment images automatically, based on a certain metadata.

I am importing photos and the field that interests me is the IPTC field caption / description. I would like to generate tags from text in this field.

For example the IPTC caption / description field might state : Dan went to the large supermarket with Shirley in a Ferrari.

I would like to match existing tags such as Dan, Shirley and Ferrari.

I am using Justified Image Grid and Media Library Assistant (MLA) plugins. MLA seems quite versatile, especially with image attachment tags, but I am not sure if it is capable of doing what I need.

For the time being, I can place the IPTC metadata, using MLA into a custom field. To link this to tags, I’m at a loss.

I was hoping to be led in the right direction. Thank you for your replies.