Thanks for reaching here! I am afraid the answer is no, we aren’t currently looking to update the functionality to allow more than one synonym map to connect to a field.
But Could you please elaborate on your need to do this? You can define many, many synonyms in a single map: dog == animal, puppy, canine, German Shepherd, etc. which should provide plenty of room for you to define all of the synonyms you need for a given field within a single map.
Having said that reaching-out to you internally to understand more on this.