Help master BL streamer for arduino (Connectivity BOX)

Hello community,

I am working on connectivity box prototype. It needs to be able to get wireless data over 4g/3g and GPS and send it through BL

I would like to base this project on Arduino. I have found a really nice Arduinio shield which presents most of the features I need (3g/4g/GPS) based on the IC LE910.

https://www.cooking-hacks.com/4g-gps-3g-gprs-gsm-gps-lte-wcdma-hspa-shield-for-arduino/

The idea is, that this box needs to be able to connect to bluetooth peripherals. For instance, commercial wireless speakers. My problem is that so far I have not found a good approach for that. 99% of the information you can find related to Arduino + BL is having arduino acting as slave, but not as a master device.

So far the best approach seems to be smt similar to RN52SRC IC, but I have not found much information.
https://learn.sparkfun.com/tutorials/rn-52-bluetooth-hookup-guide

I that tutorial, the present the IC and use it as an slave device. It seems that with the latest firmware of RN52SRC it can also work as a master device.

Can anyone help here? Any idea for better approaches? Any experience with this BL module? any help is welcomed.

Thanks in advance