Sounds like you're trying to outsmart Google.
Here's my advice: If you have a legitimate reason for creating independent blogs, then by all means do so, but do it out in the open where everyone, including Google can see it, because Google will see it anyway. They have tools of detecting "administratively related" sites that we can't even comprehend. It goes way beyond ip addresses, class c subnets, Google analytics profiles or whois registration data. if you have a relationship with a group of sites, chances are they will figure it out algorithmically.
As an example, the Theme Forrest folks do a great job of this with their collection of websites (try the drop-down navigation in the header to see the relationships) But aside from navigation, there is not a lot of inter-linking between these sites to my knowledge.
It's actually pretty common to run a number of sites under the same company. Danny Sullivan runs Search Engine Land and Marketing Land, and has a number of other sites. These all link to each other naturally.
But be careful. If you're doing this solely for SEO benefits, the temptation to optimize your links and overdo it may be too great, and you may end up in a place you didn't intend. If, on the other hand, the different sites can all stand alone on their own merit, this may be a great idea.
Best of luck!