dhclient on a link shared with static IP addresses?

[Don Cohen]

I'm trying to use a single link to connect to two ISPs, one of
which has assigned me a static address.  For the other one I want
to run dhclient.  When dhclient gets the address it deletes my
static address!  Is there a way to tell it not to do that?
I don't see anything in the doc about that.
I can't be the first one who ever wanted to do this, can I?