Hi Yannick,
You can modify the URL that you use to open the browser form to navigate back to that Web site, but it will happen even if they don't submit.
We have a qRules plugin that will launch a Web page on a button click, but it requires the plugin and sandbox has to be enabled for the SharePoint site.
A simple workaround maybe is to just switch to a new view that has a link to open the Web page. The user will have to click the link, but it's easy and out-of-box.
Best,