Can I create a sub row under an autogenerated number without creating a new auto generated number?


We use the autogenerated number field to create work orders for a service company. If the original work order needs to have sub tasks how can I create those without every row creating a new WO (auto generated) number? Example - Work order is build wall WO# 555 then I need to have sub tasks for order framing and build wall as seperate tasks tying back to WO #555 (maybe #555-01 and #555-02)???