The ubiquitous wireless communication medium poses serious threats to the confidentiality and integrity of communication in constrained networks like Internet-of-Things (IoT), sensor nodes or ad-hoc groups of soldiers on a battlefield. Data encryption is essential for ensuring the confidentiality and integrity of the wireless network communication. We focus on the problem of group key distribution in dynamically formed groups of network nodes. One major challenge is that the neighborhood of a node is not known prior to deployment and therefore, the group key establishment protocol needs to be independent of the physical network topology. In this paper, we describe an efficient template based approach for group key establishment using only shared symmetric secrets. Our template is a logical shared secret distribution built on the network nodes prior to deployment, which ensures that any node shares a distinct set of secrets with any dynamic group of nodes and thus, is able to establish a secure group key. We illustrate our template using two secret distribution protocols: sub-set and dual one-way hash chain distributions. Compared to existing algorithms, our template approach gives flexibility to the network administrator to choose from different secret distribution protocols for fine-grained control over the security levels and performance.