I'd like to connect my phone to my empeg's aux input, but I'm already using it for my XM Radio receiver.

I know there are A/B switches that let you switch between inputs, but I was wondering if there was any sort of specialty dongle/adapter that did this sort of thing more elegantly -- perhaps mixing the inputs rather than requiring switching between them. I realize that this problem is a bit harder to solve than a simple A/B switch since the inputs may be vastly different in terms of the overall loudness, but I figure someone has to have run into this sort of problem before and come up with something. My googling has not found anything that will do the job, so I thought I'd post here to see if anyone knows of such an animal, or if I'm going to be stuck with an ugly A/B switch in my dash somewhere.