The default Line Number prohibits redundant use of line numbers. However, the line numbers are assigned numerically despite the service. In other words, you are forced to use P-101, DR-102, ST-103, but you can't have P-102, P-103. Line lists would be sorted only by number, not service-number. Using on-line Autodesk instructions, I created a new Line Group Format "Svce-Line Number". Now I can assign P-102, P-103. BUT . . . P&ID will no longer restrict me from having two or three SEPARATE lines with P-102! In Pipe Line Group Settings, there appears to be no way to prevent redundancy in the new format. I no longer get the warning that the tag is already assigned. How can I prevent redundancy in the new format?