Attunement could occur through any of the great religions, but would be tied exclusively to none of them. A person could be attuned to an "integral spirituality" while still be a practicing Christian, Buddhist, New-Age advocate, or Neopagan. This would be something added to one's religion, not subtracted from it. The only thing it would subtract (and there's no way around this) is the belief that one's own path is the only true path to salvation.

An Integral Spirituality