With advances in heterogeneous and advanced packaging strategies, differing temperature limits for safe operation have become a bottleneck for increasing computational power and performance. Thus, there is a need for effective thermal isolation between adjacent components, while maintaining effective thermal transport to the heat dissipating components. For 2.5D packages, this motivates the development of metamaterials with large thermal conductivity anisotropies such that in-plane thermal crosstalk between components can be suppressed, while cross-plane heat transfer is unimpeded. Here, we design a bi-layer structure consisting of graphite for thermal transport and aerogel for in-plane isolation to improve the thermal management of adjacent components in such packaging. Varying the percentage graphite in the system leads to a range of compositions where the thermal limits are met for both the memory and the CPU. This guides the design of a bi-layer or metamaterial structures for controlling and guiding heat within advanced packages.