[Panel Module] How to inject common header/footer into all panel pages

Hello,

I completely disabled the block/node pages, and only have used the Panel Module to created 20 different pages (with slightly different in layout).

Now, I want to add a common header & footer to all page, and to be removed sometimes later.

Therefore, I don't want to add the content one by one by editing the panel page...too time consuming...

Are there better method to inject common header/footer into all panel pages?

Thanks....