I recently had a deck built. The deck has a few places where double joists are used between beams to allow cutouts for trees. The framers used single joist hangers for the 2x6 16" oc joists.
On the doubled member they just added another member to the joist that was already hung with a single hanger. Is this common practice? - I would never have thought of doing that.
2x6s are less than 7' span between deck beams. Deck beams are 19' 2x12s on outside. 11 7/8 PSL at house and in middle.
Blue arrows to area with doubles framing around tree.