Yea. I just don't know if something like whats in the thread I pointed to will work within a block; worse a dynamic block. I guess if you place an object reactor on a block, it will get placed on all blocks that get inserted, since they all reference the same block, but with dynamic blocks, they create their own block, and I'm not sure that it would get copied over. I guess some tests are in order. I might have some time to look into that, but not sure.
Other than that I'm not sure how one would go about doing it, if not with a reactor.