A hierarchy was instituted by Irvine and his most trusted associates in various regions were designated as "overseers" or "head workers". Each worker was assigned a particular geographical sphere and then coordinated the efforts of the ministry within his area. Among the overseers were William and Jack Carroll, George Walker and Willie Gill. Irvine continued to have the ultimate say over worker conduct and finances, and his activities within their fields became regarded as "interference". Except for such annual conventions as he was able to attend across the globe, communications and instructions from Irvine passed through the overseers.