How to run specific groups in tesng.xml using ant?

[Yatios]

i have to run test according to groups in testng.xml. and which test group has to include want to give using ant.For eg.\[code\]<test name="Test1" preserve-order="true"><groups><run><include name="Group1"/><include name="Group2"/></run></groups></test>\[/code\]Here i want to give input Group1 then only Group1 should run.How to achive this? please help me.Thanks