Question: For what two teams did both Billy Truax and Lance Rentzel both play?
Context: Group B of the 2017 Fed Cup Europe/Africa Zone Group II was one of two pools in the Europe/Africa zone of the 2017 Fed Cup.  Four teams competed in a round robin competition, with the top two teams and the bottom two teams proceeding to their respective sections of the play-offs: the top two teams played for advancement to Group I, while the bottom two teams faced potential relegation to Group III. Thomas Lance Rentzel (born October 14, 1943) is a former American football flanker in the National Football League (NFL) for the Minnesota Vikings, Dallas Cowboys and the Los Angeles Rams.  He played college football at the University of Oklahoma. Group A of the 2004 Fed Cup Europe/Africa Zone Group II was one of two pools in the Europe/Africa Zone Group II of the 2004 Fed Cup.  Four teams competed in a round robin competition, with the top two teams and the bottom two teams proceeding to their respective sections of the play-offs: the top two teams play for advancement to Group I, while the bottom two teams face potential relegation to Group III. Group B of the 2004 Fed Cup Europe/Africa Zone Group II was one of two pools in the Europe/Africa Zone Group II of the 2004 Fed Cup.  Four teams competed in a round robin competition, with the top two teams and the bottom two teams proceeding to their respective sections of the play-offs: the top two teams play for advancement to Group I, while the bottom two teams face potential relegation to Group III. Group A of the 2017 Fed Cup Europe/Africa Zone Group II was one of two pools in the Europe/Africa zone of the 2017 Fed Cup.  Four teams competed in a round robin competition, with the top two teams and the bottom two teams proceeding to their respective sections of the play-offs: the top two teams played for advancement to Group I, while the bottom two teams faced potential relegation to Group III. The 49ers–Giants rivalry is a professional football rivalry between the San Francisco 49ers and the New York Giants.  It is one of the great inter-division rivalry games in the NFL.  The two teams do not play every year; instead, they play once every three years due to the NFL's rotating division schedules, or if the two teams finish in the same place in their respective divisions, they would play the ensuing season.  Since 1982, the 49ers and Giants have met eight times in the postseason (including two NFC Championship Games), the most times two teams have met in the playoffs in the NFL since that time. The Cavaliers–Warriors rivalry is a National Basketball Association (NBA) rivalry between the Cleveland Cavaliers and the Golden State Warriors.  While the two teams have played each other since the Cavaliers joined the league in 1970, their rivalry did not develop until the 2014–15 season, when they met in the first of three consecutive NBA Finals series.  The two teams have met in three straight NBA Finals, becoming the only two teams in NBA history to do so.  Of these three series, the Warriors have won two, most recently in 2017the Cavaliers have won one, in 2016.  The two teams feature 11 NBA All-Stars: LeBron James, Kyrie Irving, Kevin Love, Deron Williams and Kyle Korver (Cleveland), and Stephen Curry, Kevin Durant, Draymond Green, Klay Thompson, David West and Andre Iguodala (Golden State).  Two players, Andrew Bogut and Anderson Varejão, played for both teams during this time. The Lebanese Third Division (Arabic: الدوري اللبناني - الدرجة الثالثة‎ ‎ ) is the third division of Lebanese football.  It is controlled by the Federation Libanaise de Football Association. The 23 teams are divided into 3 groups of 8 teams each.  The first two teams of each group qualify to the playoffs and the first two teams of these playoffs qualify to the Lebanese Second Division and replace the relegated teams.  On the other hand the last two teams will be submitted to the playoffs that will decide which two of these four teams will be relegated to the Lebanese Fourth Division.  The teams play twice against each other once at home and the other away. William Frederick Truax (born July 15, 1943) is a former professional American football tight end in the National Football League (NFL) from 1964 to 1973 for the Los Angeles Rams and the Dallas Cowboys.  He played in high school at Holy Cross in New Orleans and college football at Louisiana State University and was drafted in the second round of the 1964 NFL draft.  Following the 1970 NFL season, Truax was traded by the Rams to the Cowboys for wide receiver Lance Rentzel.  He was part of the Cowboys' Super Bowl VI championship team in 1971. Wendell Edward Tucker (born September 4, 1943) is a former professional American football player who played wide receiver for four seasons for the Los Angeles Rams.  Tucker spent most of his first season on the "taxi-squad" while learning behind the Rams' starting flanker Bernie Casey.  Tucker saw action in 10 of the team's 14 games in 1968 (catching only 7 passes but 4 of them went for touchdowns), and then became the starting flanker after Casey's retirement.  The 1969 season would prove to be his most productive as, playing opposite wide receiver Jack Snow, he caught 38 passes for 629 yards and 7 touchdowns, including a 93 yarder vs. the 49ers for the Coastal Division champion Rams.  Tucker returned in 1970 but was hampered by injuries and caught only 12 passes in 12 games.  In May 1971, Tucker was traded along with Billy Truax to the Dallas Cowboys for receiver Lance Rentzel.  However, unable to regain his trademark speed because of a knee injury, Tucker retired before the start of the 1971 season.
Answer: Los Angeles Rams and the Dallas Cowboys