A true genius and innovator of the comicbook industry, Vincent Sullivan, started his own magazine company in 1943. Prior to that, he had been an artist and editor in the business for several years. It was he who bought from Jerry Siegel and Joe Shuster the character they were shopping, known to the world since 1938 as Superman. He was the artist who drew the cover of the first Detective Comics, the book in which a few issues later Batman would make his appearance. Sullivan was also, according to Wikipedia, the man who decided to buck the entrenched "standard" in the field and came out with a comic book series with just one character instead of an anthology of several different people in individual adventures.
Sullivan was not totally against the idea of comics with multiple storylines in them, though. He just knew some mags needed more than one character and some could make it on his or her own. After he had left Superman/Batman headquarters (National Allied Publications, soon to be DC Comics, he worked for the McNaught Newspaper Syndicate as publisher for their new comic line. That lasted just a couple of years before he got restless and started his own line. The Magazine Enterprises (ME) he founded would last 15 years.
One of the monthly magazines ME published was Manhunt an anthology book which had the same characters showing up in individual stories each month, each one a specialist in his or her own way at hunting down naughty men and women. In Manhunt the recurring hunters were:
Starr Flagg, aka Undercover Girl, an agent with the Central Intelligence Bureau,
Jim Fallon of the F.B.I., a G-Man with an impressive record,
Ronald Kirk of Scotland Yard, an inspector with that British law enforcement bureau,
Jeffrey Fox, aka The Red Fox, a sergeant with the Royal Canadian Mounted Police,
Jet Black, Space Ace, who with his sidekick Jak Tal is a member in the future of the Space Patrol.
Flagg, Fallon, and Kirk would be in each issue. The Red Fox would miss one or two. Space Ace would be dropped after 7 of the 13 issues and be replaced with Trail Colt, U.S. Marshal in the Wild West. Each of these stories were on equal standing with the others with no particular order being maintained and no one person monopolizing the covers.
Each of the characters had his own artist maintained through the runs (as best as I can determined). The writer for each is not known but the chance remains that the versatile and prolific author Gardner Fox was behind all of them. Certainly Fox wrote all the Starr Flagg stories as well as the short prose stories that each issue had.