Interline agreements don't tend to be promoted.
If you buy the ticket on a single ticket the bag will be checked through.
An example is Delta. When you search from Adelaide to LAX you will get various options for the domestic booking : Virgin, Jetstar and Qantas and all will show with the operating airline code. These are all interline.
So if you are on the HongKong Airlines website and it shows Virgin Australia and a VA flight number for the domestic flight it's interline and your baggage will be checked through.
Some comparison sites slightly break this theory as they will provide separate tickets and you have to collect your bags and check in etc. Though they normally display a tag of this. Therefore it's much safer when you book directly with the airline as they will only sell code-share / interline tickets.