Custom message decorations - automatically link certain text messages

Is it currently possible to add a custom integration where links appear for certain text in a message?

Currently for example, with repo rooms, you can type #XXX and it will link it to an issue:

If I wanted to type "build:149" instead, I would like it to link to a CI build or something. Would be cool to have it in a form of Webhook/REST API.

See https://github.com/gitterHQ/gitter/issues/583 and https://github.com/gitterHQ/gitter/issues/426. Also related to https://github.com/gitterHQ/gitter/issues/117