If I have got the question correct I would say no.
Lets say your preset with scene 1 has a Vox type amp and a delay, now you download a preset I have made with a Plexi and a flanger and you want to make that scene 2 of your first preset, this would not work as it is a different preset with differing things on the grid.
My preset would have to have the same things on the grid within the same layout for this to have a chance to work. All a scene is like a rig is a set of states within it, e.g. It's the same rig with differing on/off states and parameters. So similar in a virtual rig on the grid the equipment needs to be the same. A different type of "rig" would be a different preset.
It would be an interesting possibility for the future perhaps in the new Axe Edit, to take the same preset, tweak parameters and save to a different scene, the next step would be for me to share my preset with another, who tweaks it without altering the kit on the grid, who in turn shares it, and I could then save it into my original preset in a scene of choice. But the kit on the grid would have to be the same otherwise it's a different preset.
Is this currently at the time of writing possible for the scenario above, I believe not.