How can I use CSL editor, so that my webpage references use a different author format than journals?

For my thesis I'm referencing journal articles as well as web pages in Nature style. The journal article references are fine, but the web page references are not the way I want them to be. For example, I'm using a guideline report of the Panel on Antiretroviral Guidelines for Adults and Adolescents, which I want as a web page reference. If I enter the "Panel on Anti (...) and Adolescents" as the author, Mendeley automatically changes it to P. Adolescents. As for an WHO report, I want to have "World Health Organization" as the author, but it changes to "Organization, W.H.". How can I update the style in CSL editor so that web page references have different author styles?