Thank you very much for your suggestions about Bots ! I didn't see this before !
What i am planning to do here is, in a way, a bot that will listen to certain keywords on a private group, and provide formatted responses with some analytics from our internal systems related to our business. So, it's actually a bot.
What i checked so far, is that there are some bot implementations using bot accounts but none of them are in ruby ( what i am using here.. ). Since there is no driver for the Mattermost webservice API for ruby yet, i will try to do something here.
Since this will take a little more time that i have available to deliver this integration, what i will do for now is to rely on the Webhook interface for a quick turnaround.
Since today there is no official support for outgoing webhooks on private groups, i will try to use a outgoing webhook on a public channel to listen for keywords and commands and reply the information on the private groups through incoming webhooks. Let's see how it goes.
This product is awesome and i see a lot of possibilities regarding integrations with our corporate systems here.
Thanks anyway for your help and your quick reply!