It is possible for cabal.project to have two seperate build units?

Question

I want to avoid cabal dependency hell problem.

I have three packges. cabal.project

packages: schema/
          client/
          server/

Where client would depend on schema, and server depend on schema. Building schema&client or schema&server would be fine. But client and server have transitive dependency on two versions of same package.

Is it possible to group build units in cabal. So I can build schema&client and schema&server separately to avoid the dependency hell in cabal, under a single cabal.project.