Pass down parameters in composite build

Hi everyone,

I have a composite build named S

This composite build has one artifact dependency (from build A) (this builds my product), and 4 snapshot dependencies (B, C, D, E) (those are testing my product))

B, C, D, E all have a snapshot and artifact dependency on build A too, since they're testing it.

This works fine, as when I trigger on build on S, first it builds A, then B/C/D/E in parallel, then aggregates everything in S.

In summary, this looks like this : 

Now my issue is : 

I added a prompt select parameter in S named “test_options” that allows our users to chose which test build they want to perform (B, C, D and / or E)

How do I access this “test_options” parameter in B/C/D/E, or even A, so I can make a condition to execute or not the various build steps ?

I tried playing with overriding parameters (see this post), but I don't want to override it, I just want to access the value to make a condition on it.

Thanks !