Multiple artifact sources as a single changeset

What I have so far (simplified), is:

(all from the same VCS root)

Project A (first in the build chain)

|

(snapshot dependency)

|

Project B

|

_________________|________________

|                                                          |

(snapshot dep)                                    (snapshot dep)

|                                                          |

Project C                                             Project D

|                                                           |

       |__________________________________|

|

(snapshot & artifact deps on C & D)

|

Deployment Build

What I would like is to resolve the artifacts from projects A-D as a single changeset for the deployment build. I'm assuming that I'll need the Deployment Build to use a combination of snapshot & artifact dependencies, but I'm not sure whether it needs to be just on C & D only (cascading the artifacts from B & A), on all projects (A-D, with snapshot & artifact deps for all of them).

The important thing for me is that a) the builds can be split across many agents and b) that consistent binaries are deployed from a single changeset.