Can I group certain actions together?

You can make the installer perform certain actions based on a set of rules using an <actionGroup> section. This will execute more than one action based on the same set of rules. See the conditional evaluation section in the documentation for details on rule-based execution of actions. You will have to include a section like the one below inside an action list section of your XML installer project file.

      <actionGroup>
          <actionList>
          <setInstallerVariable>
              <name>installapache</name>
              <value>1</value>
          </setInstallerVariable>
          <setInstallerVariable>
              <name>installtomcat</name>
              <value>1</value>
          </setInstallerVariable>
          </actionList>
          <ruleList>
             <compareText>
                 <text>${installtype}</text>
                 <logic>equals</logic>
                 <value>server</value>
             </compareText>
          </ruleList>
      </actionGroup>