OTG sets your tablet as the host device, in other words it reads from the USB device. The host scans the OTG device on connection and reads the content and disconnecting the device requires a new read on connecting. That said, you could try a music player like Mort and ask it to scan your OTG device, although I have not tried it. Remember that the key is that disconnecting the OTG device and then reconnecting the OTG device requires a new read of the contents therefore the media app needs to refresh the media contents. You may cobble together a way to connect OTG content, but you will not have a smooth integration, if that is what you are looking for.