Instead of trying to re-invent the wheel, you may want to look at ULS (User Level Security). I'm not aware of any free 'template' that you can get for this.
Here are some links ...
step by step instructions on how to do it right
www.jmwild.com Excellent resource book which I have
http://www.vb123.com/map/ Microsoft info:
http://support.microsoft.com/default.aspx?scid=%2Fsupport%2Faccess%2Fcontent%2Fsecfaq.asphttp://support.microsoft.com/?id=207793