XML : XSLT Grouping Multiple lines

**Please assist me to achieve the below results. I have tried using some xsl template it is not working as expected **

     <Source>       <RowSet>          <Row>            <Expid>Expid1</Expid>            <Line>Line1</Line>          </Row>          <Row>           <Expid>Expid1</Expid>           <Line>Line2</Line>          </Row>          <Row>           <Expid>Expid2</Expid>           <Line>Line11</Line>         </Row>         <Row>           <Expid>Expid2</Expid>           <Line>Line12</Line>        </Row>        <Row>          <Expid>Expid3</Expid>          <Line>Line4</Line>       </Row>    </RowSet>    </Source>    

After Transformation I need output as mentioned below.

  <Source>     <RowSet>        <Row>       <Expid>Expid1</Expid>       <Line>Line1</Line>       <Line>Line2</Line>             </Row>      <Row>       <Expid>Expid2</Expid>        Line>Line11</Line>        <Line>Line12</Line>    </Row>           <Row>       <Expid>Expid3</Expid>       <Line>Line4</Line>    </Row>     </RowSet>     </Source>