I have one question:
I can select component, and I can select edge in assembly with journal.
Is it possible select component and after, select edge of this component only?
Are you working in modeling or drafting?
The workflow is the user will be prompted to select a component, then the user will be prompted to select an edge and you want the edge selection limited to the previously chosen component. Is this correct? If so, it shouldn't be too difficult; probably easier to do in modeling rather than drafting. Are you selecting a single edge or multiple edges?