1) The law does not put a limit on how many grievances may be filed at one time; the only limit (if there is one) would be found in the union or collective bargaining agreement.2) A provision stating that you have two days to respond would typically be interpreted in the law as being two (2) days from the date of filing of each grievance--so this case, if all were filed at the same time, two days total. Generally, it would be business days, not calendar days.