friskymarkets:
You can use a key (legend) to show the difference. Yes, you can have one type of line (solid) to indicate direct reports and another (dashed) to indicate indirect reports, or whatever the nomenclature is for your organization.
As for the hierarchy, you should have three levels or rows, one for each: 1st level reports, YOU, and HoDs. Then, use the different lines above to show how the first-level reports connect to you and the HoDs. Just make sure those lines don't overlap so you can clearly see the difference between your relationship to these first-level reports and the HoDs relationship to the same people.
We might not have understand this properly (or you understanding us!), so please advise if we can clarify.
Can you post or DM a picture of the org chart once you put together a sketch? A visual might be more helpful than typing it out.