One of the coolest features of the Samsung Galaxy S4 is Group Play, which lets you connect other Samsung Galaxy S4s up to yours so you can use them as extra speakers to create a surround-sound stereo of sorts.
While the feature is definitely cool, there is a downside. It can only be used on Samsung Galaxy S4s. Eventually, when the Galaxy S3 and Galaxy Note 2 get updated to 4.2.2 (or 4.3), we'll all be able to use Group Play.
Until then, we have an alternative solution for you, and it works for most Android devices, not just Samsung ones.
How to Get Group Play Without Group Play