Question about Multisites

Hi,

I hope someone can clarify a few things for me.

I have a wordpress installation on domaina.com but want to create domaina.com/blog/ – my initial thought was to create a new database and simply to a fresh new installation in the /blog/ folder on my server.

What I want to be able to do though is to share some plugins between the two installations. So, for example I use NextGEN Gallery plugin on domaina.com but I do not want to have to install it again on domaina.com/blog/ and duplicate uploading the photos and maintaining two galleries.

I also want to be able to be able to search on domaina.com and domaina.com/blog/ and bring up the results of both installations.

Is this possible with a multi-site?

Thanks in advance.