displaying latest on external webpage

I have two wordpress blogs, in subdomains, for which I’d like a master page that displays the latest posts in each blog. Intense googling got me several options, including a php function called “newest.php”, and a longer version which uses an include of wp-blog-header.php to do its job. Neither worked.

This main entrance page is a step above the two wordpress installations (in root), so it seems like it should be easy enough to treat it like a quasi-wp page, in which case the only issue is figuring out how to get the page to understand that in the first instance, [the_content] should come from subdirectory A, while for the next set [the_content] comes from subdirectory B. However, WP is set up to just assume that what posts you want are coming from whereever you are. I’m not sure how to work around that, and so far I’ve managed to get, well, nothing.

Any ideas? Anyone done something similar, and willing to share code/experience? Thanks in advance.