I can't believe I have to specify this, but this isn't an NSFW group. Therefore, don't send NSFW content in the group chat. Nobody wants to see whatever foul trash you indulge in. There's no way there's something explicit that you're so enamored by that you direly need to show it to everyone in the group, so you're probably just doing it to either troll or be weird. It's not funny, it's not quirky. It's just gross.

-"Hardcore" NSFW content will result in a ban, no negotiation. Sexually explicit content, fetish content, gore, hateful rhetoric, overly disturbing content, etc. will result in a ban. This group isn't the place to promote that garbage, but I'm sure that probably doesn't mean much to you.

-"Softcore" NSFW content that isn't necessarily explicit but still suggestive, fetish content, or disturbing will also result in getting kicked or banned depending on the severity.

-Anything that violates Steam's ToS will be reported and result in a ban. No negotiation.

To conclude: Find something better to do with your time. Get a hold of yourselves and do something productive instead. It shouldn't be that difficult to just not be a weirdo.