How to index websites in reserve?

Question

Search Engine Optimization

For example, there is a canonical tag - you can specify the main page there if there are duplicates. And if I make three identical sites that differ only in domains. And in two of them you can do something like canonical to the first site. To somehow glue all three, but only one had priority in ranking.

The essence of the question is if the main domain is taken away with the replacement of content, or if it is completely separated. To get traffic back to spare domains.

Answer 1

this does not work