Can I use an LTM HTTP Monitor to monitor a DNS Entry?

Problem is that I have to use the F5 to Load balance outgoing internet traffic out of two firewalls. I've set up a group with both firewalls in it and a virtual server set as a Performance (Layer4) with a source & destination address/mask of any and service port of any and tied it to the pool. So far, so good. However, one of the health monitors that I would like to set up is an HTTP monitor to a website (see below), I would like to set the destination as a DNS entry rather than an IP address for he obvious reason that the IP may well change! I have entered in the DNS name in the Alias-address but it just resolves it and sticks the IP address in.

Is it possible to do what I want or shall I stop losing hair over it and think of another way of testing the route out of both firewalls.

Thanks in advance!

ltm monitor http Check-W3C {
    adaptive disabled
    adaptive-divergence-type relative
    adaptive-divergence-value 25
    adaptive-limit 200
    adaptive-sampling-timespan 300
    app-service none
    defaults-from /Common/http
    description none
    destination 93.184.220.20:http
    interval 5
    ip-dscp 0
    manual-resume disabled
    partition Test
    password none
    recv "HTTP/1.1 200 OK"
    recv-disable none
    reverse disabled
    send "GET / HTTP/1.0"
    time-until-up 0
    timeout 16
    transparent enabled
    up-interval 0
    username none
}