Question: What do Constantine Maroulis and Feargal Sharkey have in common? 

full_context: Document 1: Constantine (album): Constantine is the solo debut album of rock singer Constantine Maroulis. It debuted at number 75 on the Billboard 200, selling around 9,000 copies in its first week.
Document 2: Constantine Maroulis: Constantine James Maroulis ( ; born September 17, 1975) is a Greek-American actor and rock singer from Wyckoff, New Jersey. He was the sixth-place finalist on the fourth season of the reality television series "American Idol", and received a nomination for the Tony Award for Best Performance by a Leading Actor in a Musical for his role in "Rock of Ages". He starred in the title role in "Jekyll and Hyde" on Broadway, for which he received a Drama League Award Nomination for a Distinguished Performance Award.
Document 3: Loving You (Feargal Sharkey song): "Loving You" is pop vocalist Feargal Sharkey's second single as a solo artist, released in 1985. The single's two tracks did not feature on Sharkey's self-titled 1985 debut album "Feargal Sharkey".
Document 4: John Lloyd Young: John Lloyd Mills Young (born July 4, 1975) is an American actor and singer. In 2006, he won the Tony Award for Best Leading Actor in a Musical for his role as Frankie Valli in Broadway's "Jersey Boys". He is the only American actor to date to have received a Lead Actor in a Musical Tony, Drama Desk, Outer Critics Circle and Theatre World Award for a Broadway debut. Young sang lead vocals on the Grammy-award winning "Jersey Boys" cast album, certified Platinum by the Recording Industry Association of America. Young reprised his role as Frankie Valli in Warner Brothers' film adaptation of "Jersey Boys", directed by Clint Eastwood and released June 20, 2014.
Document 5: Athan Maroulis: Athanasios Demetrios Maroulis (born September 22, 1964) is an actor, vocalist and record producer born in Brooklyn, New York. He is the older brother of singer Constantine Maroulis and also has a sister, Anastasia.
Document 6: Jonathan Groff: Jonathan Drew Groff (born March 26, 1985) is an American actor and singer.
Document 7: Someone to Somebody: "Someone to Somebody" is pop vocalist Feargal Sharkey's first single of 1986 and last single of the year to be released in the UK. The b-side for the single "Coldwater" was exclusive to the single, an instrumental written by Sharkey himself. The song was taken from Sharkey's self-titled solo debut album "Feargal Sharkey". A promotional video was created for the single which featured Sharkey performing the song in a restaurant.
Document 8: Feargal Sharkey: Seán Feargal Sharkey (born 13 August 1958) is a singer from Northern Ireland most widely known as the lead vocalist of pop punk band The Undertones in the 1970s and 1980s, and also for solo works in the 1980s and 1990s. His 1985 solo single "A Good Heart" was an international success. After becoming less musically active in the early 1990s, he has performed various roles supporting the UK's commercial music industry, winning several awards and honours for his work in that area.
Document 9: Paul McLoone: Paul Martin McLoone is an Irish musician, former radio producer, voice actor, voiceover artist and radio presenter best known for being the co-creator and co-writer of the Irish comedy sketch series, Gift Grub. He is also the lead vocalist/frontman of the Northern Irish pop-punk/new-wave band The Undertones, having permanently replaced Feargal Sharkey when the band reunited for a series of live appearances which occurred in November 1999. He hosts the weekday evening/night-time radio programme on the Irish national and independent radio station, Today FM titled "The Paul McLoone Show" which broadcasts from Dublin every Monday to Thursday from 9pm to midnight and which focuses on less-known Irish solo singers or bands, as well as those from other countries who are popular in the alternate and indie rock world, but who have yet to crack the mainstream line of the music industry.
Document 10: Out of My System: "Out of My System" is pop vocalist Feargal Sharkey's last single of 1988 (not including promo single "If This is Love") and second single from his second album Wish. A promotional video was filmed for the song, and Sharkey performed the song on the Dutch show TopPop.
Document 11: Scottish music (1980–1989): During the 1980s, Scottish music featured post-punk bands exemplified by Simple Minds and Josef K, and bands like Runrig that remained closer to the Scottish dance music tradition. Folk rock or Celtic rock bands launched in the 1980s included The Waterboys and The Proclaimers. Among the folk singers of the time were Dick Gaughan and Bill Drummond, and Ewan MacColl who died in 1989.
Document 12: Konstantinos Markoulakis: Konstantinos Markoulakis, born in Athens in 1970, is a Greek actor. He graduated from Athens College and he studied in Dramatic School of National Theatre. Since 1991, he has been working continuously in theatre, cinema and television. He has played in successful TV-series and he has won a television award for the TV-series Etsi Xafnika, in 2005. He has also won an Odysseas Award in 2013 London Greek Festival for the film "The Telemachy". Markoulakis is active in politics and he was candidate with Drassi.
Document 13: Feargal Sharkey (album): Feargal Sharkey is the first solo album of former Undertones singer Feargal Sharkey. The album was released in 1985, peaking at #12 in the UK and contains Sharkey's best known single "A Good Heart" his only No. 1.
Document 14: George Constantine: George J. Constantine (February 22, 1918 in Southbridge, Massachusetts – January 7, 1968 in New York City) was a racing driver from the United States. He competed nationally in 108 races between 1953 and 1962, winning 17 times. Mr. Constantine was the United States Sports Car Driver of the Year in 1960. He won the 1959 Nassau Trophy race and the 1956 grand prix at Watkins Glen, N.Y. (in a Jaguar D-type). He set course records at Lime Rock, Conn. (1:05.81), and Marlboro, Md., in 1958, and he was one of the top-rated competitors in the 1959 Daytona, Fla. international speedway race. Mr. Constantine was known as the "King of Lime Rock" and "The Flying Greek." His most famous car with the most victories was the rare and fabulous Aston Martin DBR2/1 (owned by Elisha Walker, Jr.), and his mechanic was Rex Woodgate.
Document 15: Listen to Your Father: "Listen to Your Father" is pop vocalist Feargal Sharkey's first single as a solo artist, released in 1984. The single's two tracks did not feature on Sharkey's self-titled 1985 debut album "Feargal Sharkey".
ground_truth: singer