User Interface Selection for adding an extra dialog in the Installer

[werloblll]

I wanted to add an extra dialog in the installer(.msi file ) created through Wix toolset , i am using an user interface as MyInstallDirDlg it has got XML code for the installation process what if i want to nsert a dialog just before it , do i need to create another wxs file may be something like MyInstallDirDlg or i can/should add the functionality in the same code and if yes then how should i do it?Thanks