At the absolute level, we are all one. There is one single entity which contains everything in existence. At our relative level, there appears to be separation and individuality.
I might have this wrong, but I don't think the Subjective Reality model ever specified that our planet (or even our universe for that matter) is all that exists. I believe your conflict arises from such an assumption.
Imagine instead that there may be many such layers of consciousness going down from the absolute level at which we are all one. In this view, Spirit Guides would simply be entities that reside on a higher level (relatively speaking).
Also, if you were God would you have created just this one reality? I, for one, believe our reality is just one out of a very large number of other realities.
How does this all reconcile with SR? Imagine dropping a pebble in a pond. When it hits, it sends out waves, influencing the state of the pond around it. Imagine that in the same fashion, your thoughts affect our current reality. When you drop the pebble, it only affects a very small area of the pond. Similarly, our thoughts could be localized only to our reality, so it would be fair to say that the sum of our thoughts creates our reality, and that our reality is a smaller whole in itself, sort of like a cell in the absolute whole.