Errr, your quite wrong there bud.
When you group stuff together, it is local to the editor only. Invalid brushes are caused by a face from a particular brush not being flat.
And, always remember, quality over quantity, bigger minds don't build more open maps, with long levels and things, if thats what you mean.
Also, I recommend you re read your posts before you post em, quite a few spelling errors, the internet is not going to run away.
From a personal stand point, you seem new to forums or are young. You seem to be having a rough beginning, people might be giving you shit over the next few months or year or whatever, listen to what they say but don't take it personally. Half of us start out fine, and the other half will get flamed and yelled at and spoken about negatively, I started out like you, exactly like you. But no matter how we start, we all grow to achieve greatness in the end. If you have any problems, send a pm my way.
Nice avatar btw, you got good gaming taste