In adherent cells, actomyosin contractility is regulated mainly by the RhoA signaling pathway, which can be controlled by op- togenetics. To model the mechanochemical coupling in such sys- tems, we introduce a finite element framework based on the dis- continuous Galerkin method, which allows us to treat cell dou- blets, chains of cells and monolayers within the same conceptual framework. While the adherent cell layer is modeled as an ac- tively contracting viscoelastic material on an elastic foundation, different models are considered for the Rho-pathway, starting with a simple linear chain that can be solved analytically and later including direct feedback that can be solved only numer- ically. Our model predicts signal propagation as a function of coupling strength and viscoelastic time scales and identifies the conditions for optimal cell responses and wave propagation. In general, it provides a systematic understanding of how biochem- istry and mechanics simultaneously contribute to the communi- cation of adherent cells.