Traditional methods like CPM and PERT fall short in resource-constrained environments due to their assumption of unlimited resources. By aligning the Project Resource Management and Project Schedule Management knowledge areas, this work proposes a tool to support portfolio management through optimized assignment of project managers based on their capacity. The tool integrates a mathematical model and a heuristic approach to generate feasible schedules that avoid over-allocation of project managers. A case study at an automotive company was conducted to evaluate the tool's effectiveness in improving capacity management and scheduling decisions. Results indicate that the proposed approach enhances planning efficiency and supports better prioritization across multiple projects. The tool also enables scenario analysis, helping decision-makers assess the impact of shifting priorities or resource changes. Implementation results show reduced project delays and improved workload distribution. These findings suggest practical value in dynamic, multi-project environments where resource limitations are a critical constraint. Additionally, the tool fosters cross-functional transparency and supports proactive decision-making by providing real-time visibility into project manager workloads. Future work may explore improving the algorithm and explore the use artificial intelligence to adjust forecasting and real-time reallocation.