Identity Namespace & Batch Journey

I need to configure that some Identity Namespaces be unique in Identity Service:

1. IdentityA - entity 1
2. IdentityB - entity 2
3. IdentityC - entity 3 

Additionally I need to configure the priorities. That is in the description of the priorities:

Segmentation service: For each merged profile, segment memberships are recorded under the identity with the highest namespace priority.

1. Lets assume that some customer has both IdenityA and IdentityB. However IdentityA has a higher priority. 

2. I configure the audience and different people fall into that audience (some has IdentityA, some has IdentityB and some has both). 

3. However when I create batch journey I need to choose the namespace.

Does the people which fall into the audience which has IdentityB fall into that journey if they do not have IdentityA and IdentityA is the core namespace for that journey?