The GroupType is used to indicate the type of ad grouping that an event takes place either within or upon.

Value	Enum Value	Description
Null	0	No group. This is the default if an event does not take place in the context of a group
Category	1	Indicates that an event takes place either: To an ad while the list of ads was filtered by category, or To a category itself (such as clicking on a category)
Collection	2	Offer displayed in the typical pre-expansion/post-expansion fashion
Modal1	3	Offer displayed as the merchant modal html