Welcome to the forums and thanks for your interest in our services.
Unfortunately there is no such app or player that you can embed into a Facebook group. You will only be able to share the stations page url or the tune-in link itself. Besides, due to the the way that people use Facebook there probably would not be much point as they are constantly navigating around the site. So at least by sharing the link they can open this in a separate web page or player and continue to browse Facebook as normal.
(Admins, hope this is OK, please delete if not appropriate)
We now offer a service that allows you to put a player onto your Facebook Page/Group which would be compatible with any Shoutcast or Icecast servers. There is more information on our site here. Although as mentioned by Support above, this would only work if the person stays on that page.