I just viewed videos on Youtube with seamless blending of different Celtic Woman singers from the original to the current group.
Amazing Grace
https://www.youtube.com/watch?v=A4J1hz1KaAg&lc=z22tyd5jayvdy3eetacdp43adqth5w3xoji0k4yzpwhw03c010c.1542660293275584You Raise Me Up
https://www.youtube.com/watch?v=suN82Jdg0xU