No, PDFEdit isn't capable of merging PDF files. I've installed the application and based on the available buttons, you can Open, Save, Add Text, Images, Colors, View, and add Annotations. There is no Merge function available withing PDFEdit.
You'll need another application for this process and luckily there are plenty available to choose from.
Visit the following link and choose an app you see fit, install it and then files can be merged.
