Asterisk AGI Opration

i write dial plan same as follow
2-exten => 1111,1,answer()
3-exten => 1111,n,AGI(px.php,${ODBC_pdxi()})
4-exten => 1111,n,background(pvoice/Other/EUR)

in line 3 there is px.php that content of it is same as follow
$agi->exec(“Background pvoice/100”);
$agi->exec(“Background pvoice/200”);
$agi->exec(“Background pvoice/600”);

for example
i need when $agi->exec(“Background pvoice/600”); is playing the file, detect user key and break agi and go to line 4 or 5 or 6 according to user key

please help me