masselements into viz 2005

I've got a little problem with an architectural model i'm knocking up at the moment.
when i try to apply materials to the objects that are mass elements (created in adt 2005)rather than treating them seperately based on their individual layers it just changes all the mass elements in the model (i think based on their parent type)
any thoughts anyone?
best to scrap it and start again?
i'm fairly sure i've got the file linking correct only thing i can think of is the 'Derive AutoCAD primitives by:" option in teh file link manager advanced option, but this greyed out so i can't change it.
help...

if you right click an object and choose "convert to editable mesh" then select the faces you want to have a perticular texture on, that's one way you can go about it.

In addition to Kroke's suggestion; as these are massing models
not something further along, I would suggest that you NOT link the file
and use the 3DSOUT command and then it will most likely translate
out of ADT as an editable mesh directly. Or import the DWG directly.
The reason I suggest not linking the file at this juncture is it is only the
massing model, if it was further along then linking would be preferable.

thank you both - help appreciated. figured out another way in the interim - bit obvious really (but tedious) just set up a bunch of different mass element styles, then viz treated them all seperately and i was able to apply different materials to my hearts content.