ashish100 0 Newbie Poster

Hi,
I am using Apache's mod_rewrite module in order to enabling url rewriting.I have some queries.
(1)My website has a large database and large no. of files.I want to apply rule on only one file.So every time some event occurs(user clicks on any link to open the corresponding page) control goes to that specific file for which I have given rewrite rule.So every time this particular file got hit.That is acceptable but up to a certain level.So I want some rules or conditions that checks each file before applying rewrite rules.
(2)Second problem is I don't know how to give more than 1 rewrite rule in .htaccess file(joking, I know how to give but don't know how the control flows down).Actually in my file it tracks the first rule and if I give more rules it gives warning.So I think I must give conditions.But not aware of rewrite condition that well.
(3)The server which accepts request made by my website is dedicated server.So should I write rule in httpd.conf file or should I continue with my .htaccess file.what would be better.My site has a large user base including thousands of groups.Is there any repercussion of .htaccess file.Is there any kind of threat in using .htaccess file along with rewrite rules.
Consider me as a beginner. AND help me out plz.
Please give me a code snippet that I can use.

Thanks
slash