使用R识别和分组相关的观察，基于逻辑条件和它们发生的时间

I have a dataset ("bids") that is composed of series of observations (~5 million) each of which represents a bid to purchase a product (in the simplified example below, either a book or a game). For each observation, I have (see example data below):I have a dataset ("bids") that is composed of s