To be precise, everyone is currently condemned to hell who does not believe on the Lord Jesus. If, under your soteriology, someone is sitting on the fence trying to decide, they are condemned to hell because, by definition, they do not believe in our Lord Jesus. It's difficult to say "..sin is condemnation to hell" but not part of original sin because everyone is a sinner and that is because of original sin.
It's all part of the same curse. That original sin curse said we would die. The wages of sin is death. The two are interconnected.
That would include groups like LDS or Jehova's Witnesses. Sorry.
Original sin and actual sin are, of course, connected, but should you care to examine the connection scripturally, you would discover that there is no warrant to say that original sin alone condemns to hell.
The Church does not teach that absence of believe in Jesus condemns to hell apart from anything else, either. Factors such as obedience to natural law in invincible ignorance of the teaching of the Church offer a hope of salvation to non-Christians.