[solardev]

I took the OP to mean "any one of n keys can decrypt", not "you need at least n of x keys to decrypt".

In that case... dumb answer... but couldn't you just encrypt it twice (or n times), with n separate keys? Or encrypt the actual thing with a symmetric key, then separately encrypt the symmetric key with a public keypair for each of n users, such that any one of them could regain the symmetric key for that one thing (but not anyone else's private keys).