Fast changing market conditions force SMEs to collaborate dynamically with each other for carrying out projects accordingly to customer requirements in a competitive way. In order to simplify the cooperation, a Collaborative Network (CN) of enterprises forms Partner Networks (PN), where partners define the rules of collaboration and sign collaboration agreements. This paper provides a conceptual model of a sustainable realization of collaborative projects for SME-s from the machinery domain that follows criteria for involving new members to a PN. Furthermore, the authors describe the initiation of a PN joining process and introduce the business processes classifier for enterprises partners. The main objective of research is to enable the commencement of new projects, or Virtual Organization (VO) faster for the price proposal preparation. Today there is a gap exists in the state-of-the-art with respect to a comprehensive lifecycle of PN-initiation and collaborative project management, starting from its very inception. The primary purpose of this paper is to introduce a novel model that enables a faster PN initiation process; the novel process of PN initiation covers the aspects of composing the partner network, the PN-initiation lifecycle and a corresponding architecture for PN initiation.