Multipath
From LOTR-TCG Wiki
Multipath is a fan-made rule for defining what sites to include in your Adventure Deck. In most formats, you must include sites from the most recently-released Block (at the time the format was defined), but this leaves some blocks underused and can lead to same-y matches if the latest site path is lacking.
Multipath rules permit players to include any Movie-era site path within their Adventure Deck, but may not mix-and-match from different blocks. Thus, you effectively choose Fellowship Block, Towers Block, or King Block and then only use sites from that block. In PC-Movie, this choice is made via selection of a Map card, which is revealed to your opponent before bidding is made.