Workaround or solution for join two data sources in VC

Hi experts,

i´m looking for a solution or a workaround to join two data sources in visual composer development enviroment.

I will join a standard data source from CE-Server (e.g. BI_BPM_MY_PROCESSES_DS) with one of our own reporting data source. So I don´t have the opportunity to use a backend system (e.g. a BI system) to join the data sources!

Is there an solution or workaround available?

Thanks and regards,

Bastian

P.S.: I´m using Visual Composer for SAP NetWeaver 7.2 SPS 04.