Chemical waves commonly appear in biological systems as part of signaling processes that coordinate multicellular activity, such as the aggregation of cells of the slime mold, Dictyostelium discoideum. This behaviour is only triggered when the colony of cells is sufficiently large and dense. The ability of cells to gauge their population density and collectively initiate a new behavior once a critical density is reached is known as quorum sensing. To understand the principles of collectively "counting" how many cells are present, we develop models of chemical communication within a colony of signal-releasing entities. These entities could be thought of as biological cells or simple artificial cells, nonliving microcapsules that contain catalytic material and can therefore produce chemicals. We suppose that the rates of production of chemical species are dependent on the local concentrations according to a regulatory network. In this study, we consider the "repressilator" as an example of such a network. In well-mixed systems, the repressilator network is known to exhibit either sustained oscillations in chemical concentrations or a stable equilibrium state. Through theory and simulation, we show that the emergent behaviour in colonies of repressilator cells is sensitive to both the density and number of cells in the colony. For example, decreasing the spacing between a fixed number of cells can trigger a transition in chemical activity from the steady, repressed state to large amplitude oscillations in chemical production. Alternatively, for a fixed density, an increase in the number of cells in the colony can also promote a transition into the oscillatory state. Thus, we can use the emergence of oscillations as an indicator for reaching a quorum. This response allows us to design complex, biomimetic functionality in synthetic systems. We begin to explore these possibilities with models of microcapsules that move on a flat surface in response to gradients in chemical concentrations.