Need some help with Simple Queues & Packet Marks

I want to setup a Simple Queue where I can control the bandwidth to & from a few specific sites for my users.

I know how to mark connections and packets for downloads and uploads to these specific sites. But what confuses me is how to setup the Simple Queue with the packet marks. Do I combine both the upload & download connections as the same packet mark? Or do I make two different packets for up & down & then have two separate Simple Queues?