Partial reconfiguration is a technique used to increase the flexibility of an FPGA-based system by reprogramming parts of the system dynamically without interrupting the operation of the other modules. Despite the runtime benefits offered by partially reconfigurable (PR) systems, creating and storing partial bitstreams (PBs) are becoming major concerns for system architects when the numbers of reconfigurable partitions (RPs) and PR modules (PRMs) increase. It takes significant amount of time to generate the PBs for PR systems with large number of RPs and PRMs. More importantly, when the mapping relationship between PRMs and RPs is many-to-many, several almost-identical PBs of one PRM must be stored separately which leads to inefficient utilization of the memory storage. Therefore, bitstream relocation is drawing interests from the research community as a viable solution. Yet almost none of the works are able to demonstrate a coherent method to not only create relocatable PBs for complex and large PRMs in variable-size RPs but also how to do that automatically to free the designer from the tedious and error prone manual processes. In this paper, we propose a new technique to fill that gap. The method is successfully developed for Xilinx Virtex 7 devices using Vivado design tool flow.