Yes, it should work just fine. I have a least one from earlier this year with seven cave centrelines and many surface points.
Only thing that has gone bad (for me) in recent months is that the nice entrance icons are now red Xs.

Bruce
From: Therion <therion-bounces@speleo.sk> On Behalf Of Scott Falkingham
Sent: Tuesday, 29 October 2019 17:24
To: therion@speleo.sk
Subject: [Therion] Export Multiple Caves to Single KML Model
Hi Folks,
Is it supported to export a model of multiple caves to a single KML file? When I attempt the export, the entrance placemarks of both caves show up, but only the first sourced caves centerline is exported. Not only that, all of the placemarks are grouped in a single folder.
Conversely, exporting a cave-list of multiple caves to KML works as expected, with both caves showing up in individual folders.
Thanks.
Scott