How make vertex groups available on another

You can certainly make my day if you help me solve this mystery: :frowning:

I started out doing an armature and a cat fixed to this armature(ME datablock named CAT1)
I then copied the scene so I had two scenes with the cat,(scene 1 and scene 2)
I then set out to improve my cat´s look in scene 1: I made a new ME datablock named CAT2 -and added a lot of new vertex groups so it became more realistic

So far so good. A pretty cat(CAT 2) in scene 1.

Then the problems started: I wanted to have the pretty cat(CAT 2) in Scene 2 as well instead of CAT1.
While I found it easy to use the datablock scroller and switch to CAT 2 in scene 2, I was not able to find the vertex groups of CAT2(made in scene 1)!!!
I only have the old vertex groups.
Can anyone help me???

Bye the bye: I only discovered the problem because I´m working with particles, but I don´t think it is
because of particles, you see: CAT 1 has hair/fur on its ears, that is, the vertex group EARS, this hair particles was not preserved in Scene 2 when I switched from CAT1 to CAT2 in the datablock panel in scene 2, therefore I went to particles> vertex group >density groups only to find that the vertex group EARS did not EXIST in scene 2, but nor did the other vertex groups from CAT2 made in scene 1. They only exist on CAT 1 in scene 1, and I wonder how I can make them available in CAT2/Scene2.

I have tried a lot of things but have not been able to solve the problem.

If this explanation of the problem is too thorogh to be easily understood, I have this brief summary of the problem:

How come I dont have all vertex groups of a datablock available??? The datablock was made in another scene, but I can find it in all other scene, and put it on an armature, but the vertex groups are not available, how do I fix this???