Cabling > Extract Assemblies > To Set a Subassembly of an Extract Assembly as Reference Only
  
To Set a Subassembly of an Extract Assembly as Reference Only
1. Open an extract assembly.
2. Select a sub-assembly of the extract assembly, right-click, and select Set For Ref. Only or click Edit > Set For Ref. Only. You can now only refer to the subassembly and not modify it.