continuous integration - Prevent Excessive Builds in TeamCity -

i'm running on teamcity 6.0.4. have 2 projects, foo , bar, each producing artifacts. artifacts consumed repo, , artifact produced repo consumed leaf.

my problem bar depends on foo. when foo builds, following events happen:

1. foo builds. triggers both bar , repo.
2. bar builds. triggers repo build again.
3. leaf sees 2 repo builds, means leaf builds twice.

how should fix prevent unnecessary (and inappropriate) build of leaf?

note: having foo not trigger repo may solve problem temporarily, when introduce baz (which depends on foo), have problem again:

1. foo builds. triggers bar , baz.
2. bar builds. triggers repo build.
3. baz builds. triggers repo build.
4. leaf sees 2 repo builds, means leaf builds twice.

baz forthcoming.

suggestions?