Edit 3 cam's with Pinnacle Studio 12 Yes you can

[Habby]

I have used studio for years but it was a pain because it only supported 2 cams. One in the video rack and one in the overlay. Since I shoot weddings with 3 cams I always had to create a separate project for cam 3 and then copy and paste shots from there. Well, by accident I discovered a way. Here goes....
Place cam one in the video track. Place cam 2 in the overlay track. Next, sync them up by using the auido or with a still camera flash. There are always plenty of flashes in my weddings. Next, and here is the tricky part. Over to the right on the top video track past tape 1 drag cam 3's tape. You are going to have to delete the audio track so you can't sync by audio later. make your beggining cut on tape 3 in an easy spot to find such as right in the middle of a flash cube. before you move tape 3 find on tape 1 and 2 where it should line up underneath. Cut 1 and 2 there simultaneously but don't move any thing. Next delete the audio track on tape 3 by locking the video track and hitting delete. Grab the start edge of tape 3 and drop it on the text track underneath the over lay track as closely to the cuts in 1 and 2 as possible. Once you drop it you can't move it, so you have to sync by moving 1 and 2 together with tape 3 locked. Sounds hard but it works great
habby@gtcom.net

[Richard_G]

Alternatively use a real editor that is intended for semi-pro work like this. I use Ulead MediaStudio Pro and that can have up to 99 video and audio tracks on the timeline. I appreciate if you've been using Studio for a long time and are comfortable with it you'll try to make it fit your needs, but if you've always used 3 cams why did you choose to use it in the first place. Particularly with it's reputation for being unstable and crashing regularly.

[SCDVD]

If you do very many 3-camera weddings, it would be a wise investment to buy Premiere Pro, Vegas Pro or Edius. The multi camera tools in these will save you a LOT of time to say nothing of giving you a much more powerful editor in other ways as well.

One of the best deals available is Vegas Pro 8 from B and H for $129.95 http://www.bhphotovideo.com/c/product/536041-REG/Sony_VP8Q_Vegas_Pro_8_Video.html

It is the CD only but you can download the full manual from Sony's web site. It also does not come with Sony's authoring program, DVD Architect so you would need to author with some other program. If you want to try it out first, you can download a trail version of Vegas Pro 8 from Sony's web site. If you do try it out, take the time to really learn it. It has a lot of depth and capability. Don't let the initial unfamiliarity with it prevent you from giving it a serious try.

EDIT: Scratch that suggestion (At least the price). B and H has discontinued that offer. But in any case, it would really pay off for you if you upgrade to a better editor.