@Robert Campbell - 

A dynamic CI group won’t work here—it only controls membership, not relationships.

In ServiceNow, if you want CIs to show up as Depends on under an application service, you either need Service Mapping (for real, discovered dependencies) or a custom job/Flow that runs your query and creates/removes Depends on relationships automatically.

There’s no out-of-the-box way to create query-driven dependency relationships without Service Mapping or automation.

Thumbs up if this helps, Thanks!