What does "His business here that night might have been just as much with those two men as with his brother and sister" mean here?

Question

In "The Markenmore Mystery" (1922) by J. S. Fletcher, the chief constable was talking to two lawyers about Guy Markenmore who had been murdered two days ago after his meeting with two men at "Sceptre Inn", to which he had gone after a meeting with his brother and his sister.

“What puzzles me considerably,” observed the Chief Constable, “is—how did those two men who were with Guy Markenmore at the Sceptre come into and get out of the district unobserved? My men have already made the most exhaustive enquiries at every railroad station in the neighbourhood, and we’ve got hold of—nothing!”

“Strangers, too!” said Walkinshaw.

“How do we know that?” demanded Chilford. “There are a tidy lot of men within an area of twenty miles who might have business dealings with Guy Markenmore. His business here that night might have been just as much with those two men as with his brother and sister. Probably it was.”

“Grimsdale asserts that the first man was an American,” remarked Walkinshaw. “We haven’t a plenitude of Americans in residence about here. I could count them on my fingers.”

What does "His business here that night might have been just as much with those two men as with his brother and sister" mean here?

I know that it's a long phrase, but I can't get the general meaning of it.

Answer 1

Walkinshaw has just said that the two men who were with Markenmore were strangers. Chilford's response is:

You cannot be sure they were strangers. Markenmore might have known them from before, as he has business dealings with a wide range of people. You are assuming that Markenmore came to this area to meet his brother and sister. But it is equally probable that he came here to meet the two men.

I.e.: the usual assumption is that Markenmore came to visit his siblings and stopped at the Sceptre Inn as an afterthought. But perhaps it's the other way round: maybe the main reason that Markenmore was in the vicinity of the Sceptre Inn in the first place was for a meeting with the two men, and he visited his siblings just as a blind, or because by chance the chosen meeting place was near them.

Hope that clarifies the meaning a bit!