As far as I understood you have two tenants under /conf/global i.e. /conf/global/tenant-a and /conf/global/tenant-b.
My first question would be : how did you get the two tenants inside the /conf/gobal ? if you have moved them manually from crx/de then if you go to create a content fragment model at /conf/global/tenant-a location, then as soon as your model is created it'll be moved under /conf/global(I don't know the reason, but this happens).
Solution: I don't know how feasible it'd be for you or depends on if you could move around the nodes then there is possibility.
you need to create your tenants outside /conf/global, i.e now you have three folders under /conf 1. /cong/global --> global cf modls will reside here
2. /conf/tenant-a --> tenant a specific cf models reside here
3. /conf/tenant-b --> tenant b specific cf models reside here
Now go to: 1. /content/dam/YourProject/global and set cq:conf="/conf/global" --> this will enable you to access global cf models.
2. /content/dam/YourProject/global/tenant-a and set cq:conf="/conf/tenant-a" --> this will enable you to access tenant-a specific cf models.
Edit: I realized that I replicated your problem statement rather than providing a solution for it. Suggestion: We can't populate the global cf models inside the tenant-a dam folder. If you have to implement, you should take a look at :
There is no way you can apply 2 different cloud config to a single folder property. It has to be always 1.
You cannot create tenant-a and tenant-b inside conf/global. It has to be /conf/global -> This will hold all your global content fragment models /conf/tenant-a -> This will hold all your tenant a specific content fragment models
/conf/tenant-b -> This will hold all your tenant b specific content fragment models
Now you can create the global content folder under /content/dam/project and then on folder properties set the Cloud Configuration as "/conf/global". This will allow the global content fragment models to be available under /content/dam/project/global and you will be able to create the content fragments out of it.
Same way can create the tenant-a content folder under /content/dam/project/global and then on folder properties set the Cloud Configuration as "/conf/tenant-a". This will allow the tenant-a content fragment models to be available under /content/dam/project/global/tenant-a and you will be able to create the content fragments out of it.
Same way can create the tenant-b content folder under /content/dam/project/global and then on folder properties set the Cloud Configuration as "/conf/tenant-b". This will allow the tenant-b content fragment models to be available under /content/dam/project/global/tenant-b and you will be able to create the content fragments out of it.
You should be able to keep all global CFs inside /content/dam/project/global where as Tenant A in /content/dam/project/global/tenant-a and Tenant B in /content/dam/project/global/tenant-b