Not an ideal solution but I do this with the fleet screen and work by company. Depending on my empire size I set a limit for the maximum number of ships allowed by a firm, every few years I click through each company and check their total ship numbers, any company that exceeds this number I delete. Soon enough the other firms grow to fill the gap and new firms pop up so it's an endless cycle and you only ever suffer a minor dip in transports for a short time.