I have created a MS Word document for mail merge. The data source is an MS Excel spreadsheet.

I want to insert a field to call a user-defined function --- this function should
accept a parameter and then returns a value (which should be displayed in the document). The parameter will be a field in the spreadsheet.

This is what I want to put in the field :-
= getSuburb (LaneNo)

e.g.
laneNo = 1, the document displays "Eastwood"
laneNo = 2, the document displays "Flemington"
...
...

I could not figure out how to do this. I've tried insert field or insert formula but it didn't work.

Please help.