Hello,
I believe there is no direct way to export and import style into a created group. But, what you can do is. Right click on that group that style you wish to copy over->Appearance-> Save settings as default new groups. Once that is done. Every time you create a new group, it will have that same style. So create a new group, than move those icons from those old group. Once all is move to the new one, you can delete off those old empty group. Repeat for all other group.

Thank you.
Basj,
Stardock Community Assistant.