-> create custom groups for your players of choice

This plugin is also by philippe_44 and adds another great strength for multiroom purposes to your Max2Play Squeezebox setup.  As the name indicates, this plugin lets you decide which players to group as single entities.  This way, they can be accessed and controlled more easily and without having to synchronize them if you want to play something simultaneously on multiple players. 

The setup is very easy and quick, you just need to activate the plugin from the inactive plugins list and then create a group to tick all players you want in it.  There are also some other practical features like automatic sync and group breakup timeout.  But mostly it is just a very easy and smart way to organize your players if you have multiple instances of Squeezelite that should work together. 

For this plugin, another one needs to be replaced in order to work properly together.  Here’s philippe_44 in his own words on this plugin:

The SwitchPlayer was original written by Triode and allows switching a playlist/track from one player to another.  Unfortunately, switching tracks to/from Group Players requires some special handling that I added to [the plugin] SwitchGroupPlayer.  Switching playlist also works with MWWM [Music Walk With Me] from Michael [mherger].  The built-in switching capability of iPeng is slick but it does some extra optimizations that do not always work with Group players (when switching from a Group to a device within that Group). 

So you should replace the plugin SwitchPlayer with the plugin SwitchGroupPlayer when using the Grouping feature by philippe. 

Here you can find the discussion thread and more infos on its functionality:

Group Players plugin discussion