Sorry if my suggestion was too brief.
Since you mentioned executing it from Jenkins I assumed you were executing Gatling using maven and the gatling-maven-plugin. What I am writing here only applies to using maven.
In my pom.xml I use the gatling-maven-plugin, like so:
<plugin>
<groupId>io.gatling</groupId>
<artifactId>gatling-maven-plugin</artifactId>
<version>2.2.4</version>
<configuration>
<!-- runMultipleSimulations will run all defined scenarios -->
<runMultipleSimulations>true</runMultipleSimulations>
<jvmArgs>
<jvmArg>-Djava.security.egd=file:///dev/urandom</jvmArg>
</jvmArgs>
<propagateSystemProperties>true</propagateSystemProperties>
</configuration>
<executions>
<execution>
<phase>integration-test</phase>
<goals>
<goal>execute</goal>
</goals>
</execution>
</executions>
</plugin>
If you launch your gatling project using mvn gatling:execute and no further options with the above configuration Gatling will execute all your simulation classes one after another. However, if you pass -Dgatling.simulationClass=com.mycompany.mytest (literally execute it like this: mvn gatling:execute -Dgatling.simulationClass=com.mycompany.mytest) it will only execute the Gatling simulation found in the class com.mycompany.mytest.
This is how we execute Gatling tests. The same Gatling project provides several simulation classes and we set up different Jenkins jobs to execute them separately using the -Dgatling.simulationClass property.
I hope that helps.