It’s coming in 2019.2. Guess they haven’t really pushed the news on this out there as much yet.
A Camera Stacking system for LWRP has been in the works for a long time now and it’s coming soon.
Post from a dev - Feedback Wanted: Lightweight Render Pipeline page-9#post-4314634
A video posted by one of the devs on how it will work - lwrp_ui_ux_camera_v2.mp4 - Google Drive
