Yes, we provide a solution for end-users to auto-login into their respective Salesforce community if they are already logged into WordPress. Our WordPress SAML IDP Plugin can make your site act as the Identity Provider, in which you can configure Salesforce as the Service Provider to allow users to log in to Salesforce using their WordPress site credentials. With our solution, users will be given a specific role/membership which will decide the community of the user and accordingly log the user in their respective community.
If you have multiple applications where you want to enable SSO, please reach out to us at samlsupport@xecurify.com so that we can understand your requirements and provide you with the best solution.