Offset posts of one category only

Hi,
(This could be a question for WP Show Posts rather than GeneratePress. But, hope you can suggest some codes/solution.)
I intend to offset the posts (say 3) of one category while want all posts of another category visible in a WP Show Post list. When I key in any number in the "offset" under more settings, all the posts (irrespective of the categories) are offset by the said number. Can I just offset one category and not all the categories selected? Maybe it can be achieved by some codes...