It doesn't matter. It provides everything at the same time. Let's say this attack existed:
[G][R][P][P][C]
Discard all [P] attached.
Even if you have two Psys, a... Heal, let's say, and a DRE, the DRE and the Psys are still discarded, as it provides all energies at the same time. See the Dark Metal energy? Let's use that as an example.
Here, one Rainbow is a PsyGrass energy, capable of providing a Grass and a Psychic. It's discarded, as it states that it is also a Psy energy. THe second is a Psy/Fire energy. Same deal, with Fire instead of Grass. Now, imagine that the Rainbow energy is rather called...
A DarkPsyPyroHydroThunderMetallicFightGrass energy.
Thus, it has all types within itself. And so, all energies are discarded, as it has the capacity to be all energies, all 8 at once. Thus, it is dicarded.