Selenium Grid with Ant sequential + parallel execution
Try QAF (formerly ISFW) where you can run test parallel with/without use of grid.In Your case following config file can fulfill your requirement:
<suite name="Sample Test Automation" verbose="0" parallel="tests"><test name="Set1" > <parameter name="selenium.server" value="server1"/> <parameter name="selenium.port" value="port"/> <!-- group or class or package entry as per testNG standard --> <classes> <class name="qualified name of class"></class> </classes>> </test><test name="set2" > <parameter name="selenium.server" value="server2"/> <parameter name="selenium.port" value="port"/> <!-- <packages> <package name="package name" /> </packages> --> <classes> <class name="qualified name of class"></class> </classes></test> </suite>
It's much better to use tesng or junit to manager parallel testing instead of doing it directly in Build.xml.
here is a good tutorial on configuring testng, Ant and selenium grid :
http://technologyandleadership.com/six-steps-for-complete-test-automation-with-selenium-grid/