HTTP Post parameter value dynamic data

Hi All,

I have set up the API Connector and have contact with the server:


I only have to send 1 parameter:comma separated serie of numbers (1600+)

To do that I have made a Thing 'ggnnr" containing a list of all these numbers.

But now my question…
How to fill in the parameter value with a dynamic connection to the Thing “ggnnr”

Thank you all very much for your help!

Best regards from Holland!

Marco