How to add a skeletal mesh to another w/o editing its main blueprint class

I’m trying to give a character’s pelvis bone a tail, and every youtube video i could find about adding sumn to a mesh always starts with going into the character’s character blueprint class. Due to how the game is being developed, I don’t want to alter this blueprint class. I’m ok with making more blueprints associated with the skeleton, but i’d like to avoid overwriting its main blueprint.

Is there any way to accomplish this for a game in 5.3.2? I’d like every appearance of the skeleton in the game to include the tail as if it was part of the mesh, (which for development reasons I cant just edit the character’s skeleton either)

I’m new to unreal so if it’s possible to have two character blueprint classes existing at the same time where one only exists to add the new mesh and doesnt interfere with anything else lmk