A Team Of Four

Decades ago, a superhero team with five active members would learn of a three-pronged threat to Earth, split into two duos and a solo to address the threat, then reunite in a grand finale.

Adding van Rijn to the trader team makes a group of four which could then have been divided into:

van Rijn and Falkayn, Adzel or Chee Lan;

Falkayn and Adzel or Chee Lan;

Adzel and Chee Lan -

- but Poul Anderson does not explore every combination. However, Falkayn and Chee Lan go to Beta Crucis while van Rijn and Adzel remain in the Solar System and they reunite elsewhere later. The novel ends with the team of three - four counting Muddlehead - outward bound once more. But major changes have occurred.