You can specify a filter on the target platform to remove all but one version:
<plugin>
<groupId>org.eclipse.tycho</groupId>
<artifactId>target-platform-configuration</artifactId>
<version>${tycho-version}</version>
<configuration>
<filters>
<filter>
<type>eclipse-plugin</type>
<id>id.of.dependency</id>
<restrictTo>
<version>1.2.3.2014020241355</version>
</restrictTo>
</filter>
</filters>
</configuration>
<plugin>