Favicons are specific to the domain (www.mydomain.com94). So if you have landing pages under one domain they will all have the same favicon. However, if you put your landing pages under different sub-domains (one.mydomain.com100, two.mydomain.com86, three.mydomain.com105, etc.) you could have a different favicon for each sub-domain. The only down side is you would need a WordPress install for each sub-domain because they are essentially and functionally all different websites.

Kris Black
Designer, Author & Illustrator for the Web, Comics, & Children's Books