Selecting multiple columns with merged cells

I need to write a simple function to hide several separate column sets. I can do this fine manually by selecting the sets (e.g. select Columns D:F -> hold ctrl -> select Columns H:J, etc) and then hiding them that way. However, when I attempt to select these using a macro it will select the entire range that has a merged cell as a title. For example, the range of columns D:L has a title cell called "Margin" that spans the entire range. This seems to be throwing off my macro for selecting separate column ranges.

How can I fix this?