Modify horse nif.file skeleton to mount player and Npc together

[kilos]

My goal is to mount player and companion on the dragon of the mod of "Saiden Storm", for the second chapter of my mod "EARTH-THE PLANET OF THE GODS" downloadable on Nexus.

For this reason, I have tested the "TandemTouch" and "Alternate companion idle for TandemTouch" mods, but they do not work well for dragons.

I thought then to modify the nif.file of the skeleton of the dragon, inserting a second "ActorParent" connected to a second "X-Form Actor" to create a second saddle.

With a script, I have made to mount my companion on the dragon, and it works well. But when the player tries to mount the dragon on second "Actor Parent", the face's symbol appears instead of the horseshoe symbol, and it is therefore not possible to make mount the player. I tried to insert in the skeleton a second "Entry Point" that can only be connected to the same "Bip02 Pelvis" of the first "Entry Point", but it does not work. Ultimately, the dragon can be mounted either by the companion, or by the player, but not together.

All the advice you can give me to solve the problem, are welcome.