[yocto] sharing directories between users on same machine

[Urs Fässler]

Hello,
we try to share the sstate-cache and download directory between multiple 
users on the same machine.

It seems that this don't work as yocto want to overwrite some files in 
those directories, but does not have the rights (since another user 
created them).

Is this not an use case?
- If it should work, can somebody give pointers what might went wrong
   (some missing configuration or so)
- If it can not work, can we do that differently?


Thanks
Urs