wap phone call w/ hidden number

[kaniga]

Hello,

We are developing a website which enables people to contact each other
by phone,
though we do not want to give away their actual phone number (to
prevent harrasments).

Is it possible to send an sms to one's mobile phone with a wap link
which would dynamically load the recepient's phone number without
actually revealing the phone-number but still enable the call?

Thanks,
Kaniga.