use a variable PHP in Contact Form 7

Hello,

Excuse my English, but I’m French.
I wish to send e-mail to a recipient who is stored in a variable PHP in my WordPress page.
The recipient is a computed field, and I would wish to use it in Contact Form 7.

How can I do ?

Thanks !

http://ww.wp.xz.cn/extend/plugins/contact-form-7/