Thanks for your help
In the example above which I only  used to communicate the problem, without getting all complicated with details of my multiple projects, images and petalinux.
 
The solution would be to set the following in the local.conf file or another conf file or even a append file
OVERRIDES_append = ":os" 

It was a good tip to use "bitbake -e my-recipe | grep -e "^OVERRIDES=""
to show the results of this settings

There is another example using overrides for DEPENDS here https://docs.yoctoproject.org/dev-manual/dev-manual-common-tasks.html?highlight=depends_one
Which does not explain were the "one" machine is added to the OVERRIDES variable but the actual overrides mechanism seems clearly explained in both of the example sections mentioned but where and how this is set could do with a better examples

Thanks
Andrew