problem in tab control

i have created a tab control .in that i have two tabs naming playlist1 and playlist2 with a list view.i need to play files sequencly.i need to play files at a time when i click the button.i have made it to play both playlist at a time.but my problem is wen i click button only first tab is played.wen i click next tab only those files are played..til that they are idle.i need to play both playlist at a same time