$\mathbf{H}_{n}$ in is related to the coupling induced by the measurements in the field. To be specific, let us define $\widetilde{\mathcal{I}}_{n}$ as the set of agents whose states influence the measurement $\mathbf{y}_{n}(t)$ at agent $n$, i.e., $\widetilde{\mathcal{I}}_{n}$ collects the agents for which the corresponding columns of matrix $\mathbf{H}_n$ is non-zero. In what follows, we say an agent $n$ is physically coupled to an agent $l$ if the observation at agent $n$ is influenced by the state component $\theta^{\ast}_{l}$. Typically, $\widetilde{\mathcal{I}}_{n}$ is a small subset of the total number of agents $N$. Technically speaking, the above mentioned coupling induced by the measurements can be expressed in terms of an adjacency matrix, $\hat{\mathbf{A}}$, where $\hat{\mathbf{A}}_{nl}=1$ if $l\in\widetilde{\mathcal{I}}_{n}$ and $0$ otherwise. Now, that we have abstracted out the physical coupling (physical layer) in the networked system under consideration, we discuss about the communication layer (cyber layer), i.e., the inter-agent communication network and the associated communication protocol. Before getting into the communication protocol, we introduce *interest sets* of agents’ around which the communication protocol is built. We intend to formulate a distributed estimation procedure, where every agent wants to reconstruct the states of a small subset of the agents, which we refer to as 