How to program gravity around a cylinder? (Vine growing up a tree)

With the player as the Vine growing up a tree, and other moving Rigidbodies (enemies/obstacles) along the tree, how would I go about programming gravity around the tree? Would I need unique moving gravity vectors for each Rigidbody? Note: Need the game objects to interact like rigid bodies, so forced transform would not work,I know that this code is simple with a sphere, since there is a single, stationary center point, but how could this be done for movement around a cylinder? Would it require a moving gravity vector for each moving RigidBody along the cylinder? Note: The player and other NPCs all need to be able to move around this cylinder, and be able to interact with each other like normal rigid bodies (no forced transform).