When P2 receptors (P2Rs) are activated by ATP, they trigger an array of heterogeneous Ca \(^{2+}\) responses in osteoblasts. Previous mathematical modeling of this system has identified P2Y2R and P2X7R as the key receptors involved in generating Ca \(^{2+}\) responses that transition between transient and oscillatory when ATP concentration ([ATP]) is changed. Experimental recordings of these Ca \(^{2+}\) responses have also occasionally displayed low amplitude, high frequency Ca \(^{2+}\) oscillations (flickers). To further examine this phenomenon and heterogeneity, we expanded in this study the Ca \(^{2+}\) flux-balance model of this system by dividing the cell into three compartments: cytosolic shell (within 80 nm of cellular membrane) and bulk (rest of the cell), as well as the endoplasmic reticulum (ER). We further used an R script to cluster Ca \(^{2+}\) responses. Our results revealed that the model can maintain the [ATP]-induced transitions, and that the shell compartment is likely responsible for producing Ca \(^{2+}\) flickers, while the bulk compartment is responsible for the low frequency, high amplitude Ca \(^{2+}\) oscillations. The clustering analysis yielded 19 distinct clusters, with the mathematical model identifying the contributing fluxes for each.