In this study, we propose a two-phase scenario for the origin of the first protocellular form of life, linking two RNA-world models by an explicit dynamical interface that simulates the transition of a metabolically cooperating RNA-replicator community from a mineral surface into a population of membrane vesicles. The two agent-based models: the Metabolically Coupled Replicator System (MCRS) and the Stochastic Corrector Model (SCM), are built on principles of systems chemistry, molecular biology, ecology and evolutionary biology. We show that the MCRS is easier to initiate from random RNA communities, while the SCM is more efficient at reducing the genetic assortment load during system growth and preadapted to later evolutionary transitions like chromosome formation, suggesting the former as a stepping stone to the later, protocellular stage. The switching between the two scenarios is shown to be dynamically feasible under a wide range of the parameter space of the merged model, allowing for the emergence of complex cooperative behaviours in metabolically coupled communities of RNA enzymes.