I am sitting here right now with the exact same problem. I want a link to a free product as a giveaway promotion to incent a sign-up/join but there is no way to direct the respondent to a group-based sign-up page or the (access-controlled) product, where a “Register to see this page” page should deploy. This is a good idea but execution seems humbug. I will NOT invest time and $ in this whole thing w/o author even replying to this.