Particular has a feature where you can use one layer to obscure the particles. IE, the will disappear when they go behind it and be seen when they are in front of it.
You may have to precomp your text(not sure how particular deals with text) and then turn the layer's 3d switch on. Now in particular go to the visibility settings and change the "Obscuration" pull down to your text layer.
Here's a link on trapcodes site for building a simple obscuration layer project:
http://www.trapcode-content.com/help/particular/obscure.html
Johnny Cuevas, Editor
Thinkck.com
"I have not failed 700 times. I have succeeded in proving that those 700 ways will not work. When I have eliminated the ways that will not work, I will find the way that will work."
---THOMAS EDISON on inventing the light bulb.