I have a discord server (not one related to what is discussed here).
You may know this already, but to point this out to peeps who may not know, one of the problems is that the TOS of discord prohibit any talk of suicide and, I believe, that this has caused a shut down of people here who have already tried to set up a discord server.
You are absolutely right - it would have to be covert. However, that being said if the link were made public in the general forum, even those who lurk have the potential to see the link to the site and report it.
In addition, I am not sure (and computer gurus - please correct me if I am way off base here), there may be algorithms embedded in Discord to look for key words related to suicide (although this is total speculation on my part).
It would be nice though wouldn't it? The chat, voice, and cam capabilities in discord are awesome.
: )