Enabling blockchain technology into IoT can help to achieve a proper distributed consensus based IoT system that overcomes disadvantages of today's centralized infrastructures, such as, among others, high cloud server maintenance costs, weakness for supporting time-critical IoT applications, security and trust issues. However, meeting requirements posed by IoT in blockchain domain is not an easy endeavour.  proposes Hybrid-IoT, as a step towards decentralizing IoT with the help of blockchain technology. Hybrid-IoT consists of multiple PoW sub-blockchains to achieve distributed consensus among IoT devices and an inter-connector framework, to execute transactions between sub-blockchains. In this paper, we take the first step towards designing an inter-connector for multiple blockchains for IoT that is specifically tailored for the Hybrid-IoT architecture. We also provide a detailed security discussion, in order to identify threats and we provide discussion on how to cope with threats.