Does Platonism have a denomination/group/following within Christianity? I wish to follow Plato's belief of the forms and find other's who do so. Erm, question is, in Christianity is that actually a 'thing'? CS Lewis followed Plato. Peter Kreeft does...so Christians CAN but, well, how to know if you're among those who support it and can talk freely?

To clarify, the Platonist belief I am mostly interested in is the idea that everything has a heavenly archaetype that is more perfect than it, and that a bad thing made bad by being (to whatever degree) far away from its perfect, ideal form.
Saint Augustine, an African theologian who was one of the most significant post-Biblical Christian thinkers in the early church, was heavily influenced by Plato.  His descriptions of God the Father can be connected directly with Plato's Form of the Good, an immaterial, eternal, perfect entity that is the source of all good within the universe.

Given the shaping impact of this line of thought on the church, you might, in some sense, say that we are all Platonists.

With that said, I am not aware of any denomination or sect that specifically adapts the rest of Plato's theory of the Forms to Christian belief.