Folders & Multisite query

hello
i have a site http://acenik.com which redirects to a wordpress install in a folder blog/ http://acenik.com/blog/

im developing a new site now where id like to have 3 sites active on this one domain, ill be using subfolders for now with the multisite feature set to true

im facing a difficulty trying to achieve this

1.I Want my main site to be http://acenik.com with WP installed to a folder called /wp3/ for instance i jus move the index file to the root & my path stays as http://acenik.com itself with the installation being in “wp3” folder

2. However when i make a new site under the “Super Admin” tab it makes it with a address pointing to http://acenik.com/wp3/new_site/
can i have this instead http://acenik.com/new_site/