We are using one ideas portal and have it set up to have all entries land in one Ideas Workspace. Our teams then use categories to organize the idea intake and promote the ideas into Portfolio workspaces when they are ready to proceed with the idea. However, users will occasionally submit ideas from the Aha! webpage and have the option to select from multiple workspaces for the Idea to land in. We would suggest allowing for the customization of the selection of workspaces from the dropdown on "Create idea" so ideas don't get lost.