Yes you can.
If the DNS resolution for name foo.bar.com results
in an IP address on the CSS, the CSS can have a
layer 5 rule with a "redirect" to the string of
your choice.
For example: if foo.bar.com resolves to 192.168.1.2
then you could have the following:
content redirfoo
vip address 192.168.1.2
protocol tcp
port 80
url "/"
redirect "http://www.bar.com/cobrand.asp?foo"
active