I don't really think there would be. You could unwire one end of a cable and parallel that with the input to the drivers in the speaker, but there are problems. As the gain on the speakers is turned right up, the input level into the recording device would almost certainly be much too high and lead to a clipped signal. Maybe a DI box could help, although they only have a -20dB pad, or a desk with attenuators on the preamps, but I wouldn't be confident of getting a good recording. Also, as I assume that the speakers have a crossover, you'd only get certain frequencies, depending on which driver you took a parallel feed from. Taking a feed from the crossover input would undoubtedly involve soldering (which it might with the drivers, too, but not necessarily), but then leaves it open for assertions that the spirits talk on the wires between the crossover and the driver, and that therefore you won't get the voices in the new recording.
To be honest, I'd be doubtful of finding any way of getting a good recording direct from the speakers. The best bet is to use a very good quality microphone and recording device and stick it near the speaker, but that's far from perfect. Better if it could be done in a recording studio with the speakers completely isolated from all other noise. flaccon could listen in to the recording on headphones as it's being recorded and confirm that she can hear the voices.