You can copy the graphic, switch to the type tool, and paste the graphic into the text line. - This creates an Anchored object that will move with the text.
You can add text wrap around the graphic to control spacing. Use baseline shift in the type pallet to move it up or down.
Once you get it set-up the way you like, you can just keep copy-and-pasting it, but there is no way to style or find/replace it in automatically.
Edited: I take that back, you CAN find/replace with a graphic.
- Copy your object.
- Put the cursor in your text field
- goto Find/Change in the Edit menu.
Enter what you want to replace in the Find what: field.
Click on the @ symbol next to the Change to: field.
Under Other choose Clipboard Contents Formatted.
Do the replace (Change All).
So, when your text flows in, if you could have a special character added before and after your Subhead (maybe with a data merge), you could then Find/Change all instances of that special character. — Just make sure you use a character that is not used anywhere else.
You could also set-up the Sub-head with the graphics. Then save the whole piece together as a library item.
When you want to re-use the piece, drag it out of the library, and manually change the text for the Subhead. — a little cumbersome