This article proposes a model based on the integration of systemic mechanisms such as the soft systems methodology, partial least squares path modelling and the viable system model as an alternative for fostering complementarity (associativity) in Small and Medium Enterprises to improve responsiveness and adaptations in the tourism sector. The systemic method was adopted as a framework for the proposal. In this regard: 1. The soft systems methodology was used to frame the problem and propose a construct for outlining a possible solution; the methodology included a questionnaire applied to 150 actors (including SME owners and managers and government officials). 2. Partial least squares path modelling was used to statistically validate the relationships in the construct. 3. Through the viable system model, the interactions between SMEs were reconsidered to recognise contextual impacts and foster complementarity. The goodness of fit of 70% obtained for the conceptual model suggests that complementarity, as an organisational form, is possible. The soft systems perspective is considered suitable because it deals with the complex nature of the problem (SME associativity). Although the results in this study apply to the Mexican context, we suggest that this potential limitation can be offset by the multi-methodological approach proposed here, allowing the model's application to all kinds of organisations. Hence, the observations in this paper are constrained to the organisational domain. This study may enable scholars and managers to improve communication channels as well as inter-organisational relationships, emphasising the increase in the responsiveness and adaptation capabilities to facilitate associativity between SMEs in the studied sector.