Cannot connect to more than 3 peripherals at a time

[zabojad]

My application uses react-native-ble-plx to connect to 4 very similar peripherals at a time. I recently crossed an issue with a specific device where I could not connect to more than 3. The 4th call to connect hangs and never returns.

The device is a JSN-L21, runs on Android 9 and supports Bluetooth 4.2.

My question is : How could I detect that a device does not support more than 3 BT connections at a time, so that I can manage that case nicely in the app?