We present the results of matrix isolation spectroscopy experiments on mixed Ar/Xe matrices containing Li atoms produced by laser ablation of solid lithium. Optical absorption spectra of Li/Ar/Xe matrices containing similar to 0.01% guest Li atoms and approximate to 0, 3%, 10%, 30%, 50%, 70%, 90%, 97%, and 100% Xe as the matrix host an included. In all cases well defined "triplet" absorption features (i.e., three main peaks) are observed for the Li atom 2p<--2s absorption. We also present new data on the photobleaching of the well known "red triplet" absorption in Li/Xe matrices, which show changes to the fine structure observed on the sharp 655 nm component. In these dilute guest systems, the Li atom absorption line shape is determined completely by guest-host interactions, which depend strongly on the local Li atom trapping site structure. In single Rg host matrices, it is possible that the trapping site structures may correspond to single or multiple Rg atom substitutional sites in otherwise crystalline regions of the rare gas solid. In these cases, the observed tripler line shapes would be due to the removal of the threefold degeneracy of the excited Li atom 2p state by dynamical distortions of the system away from the high symmetry equilibrium trapping site structures. In the mixed Ar/Xe matrices, the Li atom trapping sites necessarily have lower equilibrium or static symmetries due to the possibly amorphous nature of these solids, and to the differences in the Li-Ar and Li-Xe interactions. The observed spectra in mixed host matrices thus contain contributions from the many and varied Li atom trapping site structures, yet they still exhibit the familiar tripler absorption pattern. While we do not settle the long-standing question as to the crystalline vs amorphous nature of the single Rg host matrices, the present observations do provide new data for the comparison of the relative importance of static vs dynamic effects on the spectra of matrix isolated alkali atoms.