IMO (and that of the Handbook) 225 section II effectively says to treat each separate building like it has it's own service entrance. Except when only one circuit (specifically allows multi-wire) is in the separate building.
225.30 only one source can feed the separate building (230.2, 230.40)
225.31 all ungrounded conductors must be disconnected (230.70)
225.32 disconnect where power enters building (230.71(A))
225.33 number of mains (230.71)
225.34 group the mains (230.72)
225.35 accessible to occupants (230.70(A)(1), 230.72(C))
225.36 suitable for service entrance(230.70(C))
