删除未在每个时间段和数据框中出现的组

I am cleaning data with multiple time periods in each data frame with multiple data frames. Each data frame has one year of data. I want to delete groups that do not appear in each time period(within the data frame), and delete groups that do not appear in each data frame. In other words, I want to keep groups that exist in every time period, across each data frame. I created data with an ID, time variable, and two variables that represent my data. My data will have more data frames, IDs, groups and variables as well.I am cleaning data with multiple time periods i