The svxlink core will support this. It just takes time to build extra functionality into our web GUI and the code to make the config files. In the meantime you can modify to your own needs.

Take a look at this KB article that briefly describes how you would make the modifications. https://openrepeater.com/knowledgebase/topic/custom-svxlink-configuration

In that article is a link to the svxlink man pages. Hope that is of help.