Crosstalk from different speaker set-ups running different subliminals

This is a question for Fire and/or Saint Sovereign.

I have three sets of mp3 players connected to wired computer speakers that are in different rooms and playing playlists of masked subliminals that are not in sync with each other and running 24 hours a day. I can sometimes find myself in spots in my house where I can hear more than one of the set-ups at the same time and, as I said before, the two tracks are not in sync.

Do you find that it undercuts the effectiveness of the subliminals if two different subliminals are layered on top of each other?

I am pondering getting some splitters and long cables so that all the speakers will be running from a single mp3 player. This would be a bit of a pain but it would meen that in these areas I would be hearing the same synced up subliminal from both sets of speakers. It might seem like an insignificamt issue but the spots where I can here more than one set-up are in areas where I spend a fair bit of time.

Thanks.