COLLECTION 01 > BUY BUTTON for Collection 1 > this script for Buy button featuring Collection 01 applied to Brandwebsite01(.)com embedded in html page
COLLECTION 02 > BUY BUTTON for Collection 2 > this script for Buy button featuring Collection 02 applied to Brandwebsite02(.)com embedded in html page
COLLECTION 03 > BUY BUTTON for Collection 3 > this script for Buy button featuring Collection 03 applied to Brandwebsite03(.)com embedded in html page
From what I understand, you can use simple button HTML with an a tag around it, directed towards the link.
<a href="#" target="_blank"><button>Button</button></a>
The target="_blank" is so that the link is opened in a new tab, the # inside href="" is where you would place your Brandwebsite01.com, etc links!
Hope this helps!
Ah I understand, I'm not sure 100% if Shopify can embed collections from one store onto another or a different site, may be something you have to ask them. What I was thinking though is you could create an image, like an "ad", and have it on the external sites which direct the user to the Shopify store collection page when clicked!
Hope this helps, thanks.