iRule, Traffic Policy or Re-Write Policy

you may see  https://hostnameA.test.com:666 in the browser for many reasons
thats why I am asking if there is a redirect response (301 or 302) or there is something else

anyway give this a try

when HTTP_REQUEST 
{
    STREAM::disable
    HTTP::header remove "Accept-Encoding"

	if {[IP::addr [IP::client_addr] equals 192.168.1.1] } 
	{
		pool POOL_A
		set selected_hostname "hostnameA.test.com"
		HTTP::header replace Host $selected_hostname
	} 
	elseif {[IP::addr [IP::client_addr] equals 192.168.2.1] }
	{
		pool POOL_B
		set selected_hostname "hostnameB.test.com"
		HTTP::header replace Host $selected_hostname
	} 
	elseif {[IP::addr [IP::client_addr] equals 192.168.3.1] }
	{
		pool POOL_C
		set selected_hostname "hostnameC.test.com"
		HTTP::header replace Host $selected_hostname
	}
}

when HTTP_RESPONSE 
{
    if {[HTTP::header exists "Location"] && [info exists selected_hostname]}
    {
        set loc [HTTP::header "Location"]
        if {[string match "https://$selected_hostname:666*" $loc]} 
        {
            HTTP::header replace "Location" [string map "https://$selected_hostname:666 https://example.com" $loc]
        }
    }
    if {[HTTP::header "Content-Type"] contains "text" && [info exists selected_hostname]}
    {
		STREAM::expression "@https://$selected_hostname@https://example.com@"
		STREAM::enable
    }
}