When using Ivy repositories how do I exclude an artefact of a dependency?

For example say this was the ivy dependency:

<dependency org="com.example" name="example-project" rev="1.2" conf="runtime">
 <exclude ext="tar"/>
 <exclude ext="zip"/>

And example-project consisted of 3 artifacts - a .jar file, a .tar file and a .zip file but I only want to depend on the jar file? All I can find is how to do exclusions in gradle with the group or module.

You can do the opposite (include jar only):

dependencies {
  compile group: "com.example", name:"example-project", version:"1.2", ext:"jar"