Client want TBD dates

Hi!
I build timelines for our client, who has little understanding of what this program does and is for (not that I am much better). They have made unusual requests, and up until now I have been able to make most of the work. Our client has asked for TBD “To Be Determined” dates. No big deal. However, they don’t want these dates to show in the Gantt. Sigh…

I have looked around, played with filters, made the object white or transparent. I still end up with a visible object in the Gantt. Our process is to export as PDF and place the PDF into InDesign to follow a preset template. Then we re-PDF for distribution.

If anyone has any input or suggestions, it’s appreciated. Markup for clarity attached.

Thanks, Christian