In this paper we develop a theory for the region-based synthesis of system models given as place/transition-nets with weighted inhibitor arcs (ptinets) from sets of scenarios describing the non-sequential behaviour. Scenarios are modelled through labelled stratified order structures (LSOs) considering ”earlier than” and ”not later than” relations between events [6, 8] in such a way that concurrency is truly represented. The presented approach generalizes the theory of regions we developed in [10] for the synthesis of place/transition-nets from sets of labelled partial orders (LPOs) (which only model an ”earlier than” relation between events). Thereupon concrete synthesis algorithms can be developed.