I think this code might work for you. Paste it into the 'ThisWorkbook' module in the vba window:
This code is triggered when you go to either print or print preview the sheet. It goes through every row starting with Row 2 (skipping your header row (row 1) so that won't get hidden), and if the interior colorindex is not 37 (pale blue), it will hide the entire row. In your case, it hides several rows at a time since column A uses merged cells. (For once.. merged cells made things easier!!)
After you print or print preview, the rows will remain hidden, but you can select the entire sheet and then use Format -> Rows -> Unhide to unhide all of the hidden rows.
hth
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