building up a file, based on the state of an object

hiya,

Based on the state of an object, I want to build a file.

eg
if (property1 = A  and property2 = B)  Then build file1. using the the first 4 properties of the object

if (property1 = X  and property2 = Y)  Then build file2. using the the last 8 properties of the object

I think I'm looking for a creational pattern, but am unsure on the specifics.

Any suggestions appreciated.

ta,

yogi