Distance Based Volume Attenuation of Stereo Sounds

I need to be able to have a stereo sound playing from a source in 3D space without panning.

I would like the Stereo sound to get louder as you get closer to the source point and to attenuate when moving away in the same way as 3D mono sounds work. The stereo sound must maintain the left channel in the left speaker and vice versa for the right channel.

I have seen this subject approached in other posts here, but none with a satisfactory reply as the questioner is quite often just wanting a mono 3D sound, but what I'm trying to do requires a stereo sound to maintain it's panning.

I really appreciate your time :)