I am trying to develop a custom mullion profile for tilt-up concrete panel construction. I will be using a combination of curtain walls with embedded wall families as curtain panels. The curtain wall approach will make it easier to manage the "individual" panels, especially for curvilinear segments.

For appearance sake, I don't want the exposed faces of the curtain mullion profile displaying. I am seeking a clean joint appearance. In the curtain mullion profile template, there is an <Invisible Lines> category from the line type selector window. I mapped this property to the exposed face linework.

I saved the profile family and loaded it into a project and created a new mullion type and mapped the new curtain mullion profile to it.

Result:
The exposed faces are still visible in the project.

Other project conditions to be addressed:
In this project, there will be a combination of curtain wall types where mullions will need to be visible and invisible. Therefore, using visibility/graphic settings will not work in this context. This type of construction is the primary shell envelope.

Workarounds attempted:
A) Experimented with linework Visibility turned off for course in profile family. Same results above.
B) Fact: Mullion profiles require a closed loop.
C) Split Walls With Gap. Unfortunately, this splits the curtain wall and not the embedded wall. A tab selection set process to access nested elements would be beneficial here.

Questions:
1) What is the purpose of <Invisible Lines> in the mullion family?
2) Is there a way to create sub-categories in the mullion family? I don't see a way natively.
3) What other suggestions can be explored?

Thanks in advance for your help!
John Herridge, AIA