text: Title: Data Generation Overlap for Multiple DataFrames
  Body: #### Concurrent Data Generation Strategies for Multiple DataFrames
  
  I realize this may be a difficult functionality to implement, but at a high level I am thinking about the best way to use pandera data generation in unit tests for testing functions that involve some merging across multiple datasets.
  
  In one of my use cases I have a function that merges two dataframes on their shared timestamp column. I have pandera schemas defined for both of these dataframes, the timestamp data should be at an hourly frequency.
  
  So I am wondering if you have any thoughts about how I could ensure that when data is generated, they have the same date range so that the function which contains a merge operation can be effectively tested. I guess one workaround would be to define a function that generates a date range with length equal to the length of the dataframe, and then overwrite the timestamp column in both dataframes. But maybe you all have some different ideas or I'm missing how to do this already?
  
  Thanks! I can add the enhancement label if it's appropriate.
  