Wireless Ad-hoc and Sensor Networks are the cornerstone of decentralised control and optimisation techniques in numerous sensor-rich application areas. Triggered by the necessity of autonomous operation within constantly changing environments, Wireless Ad-hoc and Sensor Networks are characterised by dynamic topologies, regardless the mobility attributes of their operational nodes. As such, the relative awareness that each node can obtain of the entire network draws the roadmap of viable reconfiguration mechanisms, such as the establishment of bidirectional connectivity. The issues addressed in this paper are related to the bidirectional connectivity conditions over Wireless Ad-hoc and Sensor Networks. Based solely on the relative awareness that each node has of the entire network, sufficient end-to-end connectivity conditions are herein extracted. These conditions, exploiting the notion of relative Delaunay neighbourhoods, formulate the basis of a transmission power adjustment scheme. Without any additional network overhead, the resulting Relative Delaunay Connectivity Algorithm is herein proven to yield an efficient solution to the connectivity issues. Extensive simulation results are offered to evaluate the performance of the network, resulting from the proposed transmission range adjustment, whilst highlighting the benefits of the Relative Delaunay Connectivity Algorithm.