delay pools and VIP

Trying to make sense from delay pools:

Let's say I need priority access for a single IP (let's call it VIP).
Whatever bandwidth that IP asks for, it will get it. If inactive, other
IPs will get unlimited access. Seems to me I can't set delay pools to do
exactly that.

Given our capacity of 3000 B/s, I can say that VIP can have no more that
2500 B/s, and other IPs can have no more than 1500 B/s. That's fine when
both VIP and IPs are surfing, but when VIP quits, the IPs are still
limited to 1500 B/s, right?

--
Milos Prudek