Right click on the field or fields that is irrelevant to the group.
Select Format Field.
Under Common Tab, click on x-2 button on the right of the Suppress checkbox. If you need to suppress the fields for only one change type (as you have mentioned in your post, type the following in the Format Formula Editor window that opens up
[tt]{FieldThatContainChange} ="Your Change Type"[/tt]
Click Save and Close button
Click OK
In case you need to suppress for multiple change types use the following in the formula editor instead:
[tt]{FieldThatContainChange} in ["Your Change Type1","Your Change Type2][/tt]
Hope this helps.