Jess, as I wrote earlier the phenomenon you describe has the proper technical appellation MEDLEY, i.e., a song made up entirely of a catalogue of song titles or well-known song extracts.

'Wild Rover' sung to 'Ghost Rider' is definitely not a medley. I don't know if this type has a proper name yet, probably not. In the early nineteenth century they were very common often with just the title 'Medley' or something like 'Farmer's Medley' with a theme, but they were popular in earlier centuries also.

If it included 'Wild Rover' and 'Mountains of Mourne' the chances are that it is a very modern example, i.e., post 1960.