@Bruce3 Your inclination to employ a blog page to house the filterable/searchable material is exactly right. The information for each partner organization would indeed be housed within separate blog posts and categorized accordingly. The Weebly Pro plan would minimally be required so that you would be able to perform free-form searches within the blog in addition to category filtering. You'd have to be strategic about how best to employ your categories for filter purposes. For example, if you had a blog devoted to vegetable recipes, you might have posts that have cateogories like "carrots," "potatoes," and "spinach." But you could additionally have more general categories like "root vegetables" or "cruciferous vegetables" that would apply to a wider set of posts. The key part of the category strategy is to keep your categories as compact as possible (you don't want to present the visitor with an endless list of filter categories).
If you indeed wish to pursue a blog type solution, Weebly may not be the best platform for this as it is not as fully-featured or as flexible as a dedicated blogging platform. Tags, for example, don't exist in Weebly blogs so you don't have fine-grain control over your filters. There's no such thing as sticky posts. Blog presentation styles are quite limited (unless you know how to custom style code the blog page). For greatest flexibility and an unmatched array of potential plugins that can expand the functionality of the tool, your best bet here is WordPress. Granted, this is not renowned for simplicity of the UI, however, your client would only have to confine themselves to the "Posts" area of the WordPress dashboard once the site has been built and configured. After that, they can fine-tune categories and tags and add more partners relatively easily (yes, I'm using the term "relatively" in a somewhat loose fashion here given the sometimes profound inability for some clients to understand even basic technology concepts).
