SONOS commands to group players

[david.rombaut@gmail.com]

Hello, still having a minor problem with grouping and ungrouping players.
I use KNX pushbuttons to control my SONOS players and use following command to stop the player if it's playing (1 toggle button to switch between ON and OFF)

Code:

 -- Pause if status is playing, play otherwise
 if (status_beneden == "PLAYING") then
   upnpavcmd(IP_Beneden, 1400, 'BecomeCoordinatorOfStandaloneGroup')
   upnpavcmd(IP_Beneden, 1400, 'Pause')

This works flawlessly if the player is indeed part of a group: the player is removed from the group and paused, as one would expect 
When the player is not part of a group however the first command causes some sort of stop command and the current playlist is not paused but stopped.
To illustrate this see the attached screenshots:

• screenshot 1 and 2 when the player was part of a group and was successfully ungrouped
         
  
• screenshot 3 and 4 when the player was not part of a group and thus stopped instead of paused
         
  

Seems like I would need a code to first check whether the player is part of the group so I could avoid the first command line with an IF conditional check.

Any suggestions are kindly appreciated.

Best regards, David