When you say that you would like to amalgamate/merge domains, this means that you would like more than 2 domains on the one site. This can be done in one of 2 ways
Add the domain names to your active site. Do this by clicking on the 'Domain' button in the website editor console. This takes about 24 hours for the domain to be active on the new site. Doing it this way means that people will see your site as each domain. However, Google will only pickup one domain in the search engines when people search for your site using keywords. So you would need to decide which one is your primary domain name ie which one you would like to come up in search results in Google and other search engines
You can do as above, but set a 301 redirection in place. This means that the site will only appear under your chosen domain. So even if people type one domain name into their browser bar, they will automatically be diverted to the other domain name. They won't notice anything different, except that the domain name changes. So both domains will work, however it will automatically redirect the domain name to the main one. There is a one-off cost of $49 for this to be done.
If you would like us to set a primary domain or a 301 redirect, or should you have any more queries, please don’t hesitate to let us know