fundraiser not accessible when using membership access levels

we have a need to block all posts on our website unless the user is a full member of the site. we have a fundraiser running on our site but we've found that when we block all posts the fundraiser is only accessible to full members but we need this fundraiser accessible by all users.

a url group can't be used because we already have a group setup which is needed to block a url.

is there anyway possible to allow this url with out current configuration?