DOCBOOK-APPS: Self customising stylesheets, or clever Norm!

Beginning to appreciate the subtlety of Norms titlepage.templates.xml.
[Nice one Norm]

Issue:

<legalnotice> appears twice in the book I want to print.
An actual copyright notice, and some trademark acknowledgements,
for which I have used <legalnotice> again.

Hence!

I'd like to say, in titlepage.templates.xml

<titlepage-content side="recto" ...>

<author/>
...

<legalnotice [@id='ln01']/>

to say, effectively, please put this here,
then in 
<titlepage-content side="verso" ...>

<author/>
...

<legalnotice [@id='ln02']/>


I.e. to request one from many elements
which one I want where.

Is this reasonable?

Regards DaveP