How to delay a Hudson build until its dependencies are built?

Our build consists of two projects, a library project and a web front end project that depends on th开发者_运维问答e library project.

The Hudson jobs are configured from the maven pom.xml files and the dependency appears on Hudson as downstream/upstream project. Both jobs use the "poll SCM" build trigger and everything works as intended when only one the projects changes.

The problem arises when a commit contains changes in both projects, so Hudson starts a build of both projects at the same time and usually the web project build fails because it is using an older version of the library project.

Can I configure Hudson to delay the execution of the web project build if there is a build running the library project?

Isn't the web project and the other project located in a different area of the version control? ON the other hand you can define upstream or downstream dependencies and say only start if the build went well.