This is handled via the peer-to-peer component relationships. See the following in HELP:
*Cross-Discipline Peer-to-Peer Component Relationship Example
*About Attributes for One-Line, Hydraulic, and P&ID Symbols
Pay specific attention to the WDTAGALT attribute. You may need to add it to the symbols you're using.
Post back if that doesn't get you where you need to go, I or another forum user will help get you together.
Jim Seefeldt
Electrical Engineering Technician