Hi,
You can do this by including a
<link> grammar in your IVR application root document (or at the document level of your main script, if you have a single-document application). E.g.
<link mode="dtmf" next="#formTransfer">0</link>
Note, however, that this link grammar can only be invoked when the IVR system is listening for input, so your entire IVR application may need to be composed of fields with active IVR grammars, i.e. callers would not be able to invoke a transfer while inside of the following form:
<form>
<block>
<prompt>
<audio src="file1.wav" />
<audio src="file2.wav" />
</prompt>
</block>
</form>
since there are no active IVR grammars.
Hope this helps,
Plum Support