Creating multiple networks

Here is the situation in which I find myself. I have tld.com and this domain has several subdomains of which five are WordPress installations, two of them are even MS. So let us say that a.tld.com and b.tld.com are MS and that c.tld.com, d.tld.com, and e.tld.com are not MS. I would like to move c, d, e so that d and e are just sites on the a network but that c is another network under the same codebase as the a network. How would I go about this? I know @andrea_r has a plugin for the network part, but will I also need to domain map? Obviously a and b are already setup with wildcard sub-subdomain support. tld.com is not configured for wildcard subdomain support. Is what I am trying to do even worth it? My desire was to try and reduce everything to the point of having one codebase for all my blogs. Thanks.