I don't believe it's possible to have two apps connected at the same time, although I've never tested it. I would think it's unlikely to work, but if I remember tonight when I get home I'll give it a try.
You might be better off with a headphone Y cable, although if you have a newer iPhone without an earphone jack that might not be possible. But I do see Lightning to headphone adapters, so a Y cable could be plugged into that.
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