paid subscription (use paypal) use different return url

[snowname]

I have several paid subscriptions. I use paypal to collect the payment.

After a user make the payment, they should be directed to different pages.

I think I need to change the following template.

subscription_payment_paypal
....
<input type="hidden" name="return" value="http://A.com" />
....

I should put something like
<vb:if condition="$subscritionid==1">
<input type="hidden" name="return" value="http://B.com" />
<vb:elseif condition="$subscritionid==2" />
<input type="hidden" name="return" value="http://A.com" />
<vb:/if >

The problem is how to get the $subscritionid?