Spectral filtering allows us to manipulate the collected light statistics and the resonances induced by dipole-dipole interactions give rise to specific correlations, where the time symmetry of the correlations is broken. Based on the collective dressed states, we will explain that the study encompasses both the case of real processes, where the photons are associated with specific resonances and classical correlations between each other, and virtual processes, where pairs of photons are emitted with non- classical correlations. On the other hand, the dipole-dipole interactions give rise to new sidebands in the fluorescence spectrum due to specific couplings among the collective dressed levels which in turn depends on the spatial configuration of atoms. These couplings are the main responsible for the frequencies and variety of sidebands. We will explain the general method for finding the dressed energy levels for a system of any number of strongly coupled atoms and we solve this problem for two different spatial configurations of three coupled two-level emitters. We show that the coupling among dressed levels and consequently energies and number of sidebands in the fluorescence spectrum are different for each configuration. Thus, the fluorescence spectrum of strongly interacting atoms contains information about the number and configuration of atoms.