Internet radio vs Intranet NAS connection

[Oroperplex]

getting NAS out of Internet access when playing internet radio over Linn Accurate DSM

Since years i hear my music storing on a Synology NAS with Minim Server with a Linn Accurate DSM and an Asus Router. None of this parts has access to internet. My tablet is also attached with the router over wifi playing music with Bubble. So all is Home Intranet

My idea is to hear Internet Radion over the Linn and tablet, but i do not want for security reason, that hacking kids getting access to my NAS, maybe destroying the content.

So is there somebody with a solution that NAS is still in Intranet but Linn plays also Internet radio ?