Joining selection contents?

[inducer]

I have text that looks like the following:

Useful text A
Junk
Junk
Useful text B
Junk
Junk
Useful text C
Junk
Junk

and I would like

Useful text A
Useful text B
Useful text C

I was able to get to the point of having multiple selections convering the "Useful text" bits, but then I got stuck. What do I do to get the content of the selections pasted together, say separated by newlines/commas/what have you? Is there an efficient way?

Thanks!

[MrWheatley]

I think you can use the yank_joined and yank_joined_to_clipboard commands for that.