How to find staff assessments Date during a given Month?

[Drackon]

Having trawled for hours on the web for a solution, I now turn to this forum for an answer, which may not even be possible. So here is the challenge:
I have thirty staff, each has a separate spreadsheet with various information contained on it, part of that information is regarding assessment dates and when each member of staff is due to be assessed. The problem is I'd like to create a cover spreadsheet where each staff member is listed in column 'A' and the next 24 columns represent a month followed by a blank column to be filled when the assessment has been completed, like so:
Column A = Name
Column B = Jan
Column C = check
Column D = Feb
Column E = check ...and so on.

Is there anyway excel can read each employees separate spreadsheet and then insert the day (date) his/her assessment is due in the correct month column of the cover sheet? So employee Dave is due an assessment on 5th May and another one on 5th November, can excel fill in the cover sheet to show 5 in column May and 5 in column Nov against Dave's name.

Each member of staff will have different assessment days. The objective of the cover sheet is simply to allow me to instantly see how many staff require assessments during a given month, and on what dates, so I can quickly determine my work schedule and diary. I would rather have this information all contained within the same workbook than having to keep switching between Outlooks Calendar and Excel.

Any help would be greatly appreciated.