What you are describing is called a link farm and it is a violation of Google penguin algorithm and you will absolutely get your main site deleted from the index or at least Throttled.

It’s not a bad idea if you have to protect Your brand.

It is good to create sister sites that specialize in a particular category or subcategory that you have, but if you link to your main site you must have or ReL = no follow on all the links to ensure that you are communicating that you are not trying to manipulate search results for your main site.

There are people who successfully create link farms and go undetected by Google.

You have to purchase them and host not on the same server or even company. Do not register them with Google search consul under the same account or under the same email address. I would also either hide the domain ownership information or make sure that it’s not listed to the same company.

Again I do not recommend the strategy.