format capitals in a merge field

I have a merge field drawing on a data source where the data is all in
capitals. I changed it to lower case using the \* Lower switch. But I need
the final result to be in title case, and \* Caps doesn't seem to produce
Title case when the data source is already fully capitalised. Is there
another format switch I could use? or perhaps a way of nesting the field so
it changes to lower case then to title case?

Thanks, Peter.