Hi, (unfortunately, I cannot read cyrillic, so I'm not sure who you are ;-) ) I'm Yuriy Mironenko, Rostov-on-Don, Russia :-)
My understanding is that there is no limit to the number of groups for a platform. The team size is exactly 3 developers, but I have not found such a limit on their website. I wanted to admit it in previous letter, but, well...I didn't. Mainly because this question is not absolutely clean.
Really, when you reading announcement page ( http://www.plat-forms.org/platforms-announcement (http://www.plat-forms.org/platforms-announcement) ), there are no this restriction listed in some clear manner. But you may admit this quotation: "However, we will nominate a best solution among the three solutions on each individual platform". And, when you reading main page ( http://www.plat-forms.org (http://www.plat-forms.org/) ), you may admit this quotation: "We will try to select the most capable teams from among the applications and will accept up to four (and at least three) teams for each platform".