First time asking a question here ! woo.
I've tried to look for an answer.. I must be missing something very basic.
I started using Geometry nodes a few days ago (finally)


I'm trying to scatters stuff on instances by vertex group located on those instances

[![][1]][1]

So we have those "building01" and  "antenna01" objects

I scattered building01 using a vertex group on the ground plan then random rotation, all good.
Now, i want to scatter those antennas on the top of those building01 instances.
On the building01 object i defined a vertex group called "roof"


- First i tried to make it all with one geometry node but i cannot access the "roof" vertex group. 
-I tried to stack TWO geometry nodes modifiers (one for the first scatter of building01 and a second one for antenna01). But that just... don't work. 
-I tried to make a geometry node for the building01 object, i can scatter antenna01 but just like shown on my screen capture all the instances are identical. Which of course makes sense...
- Realize instances doesn't help because i can't access the vertex group on building01 anyway :(

That's it.. actually. 


This is a very simple example but then i could have complex buildings bases and scatter/display stuff on them using vertex groups. like antennas on roof , pipes on wall, etc.

Thank you everyone

  [1]: https://i.sstatic.net/HUFIf.jpg