Just in case you want the particles to look into a certain direction you should add a find target node under the birth script. In my case I modelled a proxy all particles have to look at.
Use the settings I used. The very low speed is important here! Because we don't want the particles to move around. I checked Mesh Object and picked my proxy then.
Now every particle want's to fly to the proxy but is to damn slow ;-p
Drag a rotation node under the find target and set it to Speed Space Follow. That makes our LookAt workaround happen! Because the particles have a dramatic low speed they ONLY turn into the proxies direction without moving.
The particle shape instances will only turn towards the find target from frame 1 on because they need to be "triggered”. In frame 0 they will all look into the initial direction.
If you're happy with the result move the particle flow icon to 0,0,0 to the grid centre (that would't have any effect on your particles!). Now use a Mesh Compound Object (as well located at 0,0,0 grid centre) and pick your particle system. That converts the particles into editable polygons which can be modified just like other mesh objects. WARNING! Maybe that step might kill your max if you haven't enough RAM and will take some time to calculate!!
Now you can collapse the Mesh Compound Object into an editable poly and work with it as usual.
You can download the script as well as an assembly file from my website:
< the max script
< the max file