Ensuring a logical structure to your ERGs/BRGs is critical to long term sustainability and scaleability. As a best practice try to align the local structure as close as possible to your organizations location data. This can be accomplished by first aligning to the internal regional alignment of your organization. For example, if you work for a global company with operations in APAC, EMEA, LATAM and North America then you should align your ERGs to that same structure. From there you can drill down to local chapters. For instance, within APAC you can have local chapters based on your organizations physical locations such as Tokyo, Singapore, Melbourne.