You can copy packages from other PPAs into any PPA that you can upload to. You also have the option of copying packages between distro-series (i.e different distribution releases).
For example: take a look at the Launchpad team's PPA copy packages page.
Here you can:
- select one or more sources to copy
- select the destination PPA - you must have upload permission for that archive
- specify the destination series
- choose whether or not to also copy the related binary package.
As soon as you request the copy, the source will be listed in your PPA with details of it origin. However, it can take up to twenty minutes for the files to actually appear in your archive.
If you only copy the source, the corresponding build records are created in the destination PPA immediately.