$50 if you can help me... Amember experts needed.

I've posted this in the Amember forums but no response so far, I figure there's probably an expert or two on here.

Ok, here's the issue.... if you know your stuff, it'll be a simple issue I'm sure.

I have a site we'll call [site A] that sells one-off products on Clickbank - no membership option - not using Amember.

I also have a members site we'll call [site B] that sells a monthly membership product using Amember and Clickbank.

What I want to do is make it so that I can upsell [site B] at the point of purchase when customers are on [site A].

So, summary: Surfer arrives at [site A] reads the sales letter and wishes to purchase the one-off product... I upsell them the product located at [site B] - the monthly product plus they get the product at [site A].

Now, I need to set up Amember to be able to do that... Only one purchase option should be displayed to the user on Amember's purchase page.

So if they are on [site A] they only see the opportunity to buy the upsell product on Amember order page.

If they go directly to buy [site B] via that sites sales letter then they only see the option to buy that on the Amember purchase page.

Also, I guess I'll need to have two different thank you pages for [site B] - one for the direct purchase and one for the upsell from [site A]... Or maybe I'm wrong?

There may be further niggly little issues that I've not thought of that you may be able to highlight.

For the person who helps me with this and gives me the solution that works, I'll happily Paypal you $50 to say thanks.