Mapping from Single Text field under Items to multiple fields in target

Hi Friends

I have a scenario where under Items(0...unbounded) there is a Text field in the source structure , for every text field that comes under item it needs to be mapped to a Address Line  field like Line1, Line2, Line3 etc. up to Line10.So under first Item whatever Text comes it is mapped to first Line i.e Line1, next whatever Item comes , its Text value is mapped to Line2 and so on. Could anyone help me on this , can this be done using standard functions or do we need a udf, if we need a UDF , would really appreciate if anyone can provide code.