I've thought about this for a while and IMO the easiest way of going about
this is to add 6 columns to your Excel sheet and enter the 6 values you want
on each row there, /then/ do the merge. If you can't alter the existing
sheet, you should be able to copy it to a new one and set these columns up
in there. Let's call them Student1,...,Student6

In Word, you will need a field that ends up looking like a checked box or an
unchecked box (or however you want to do it - can there only be 2 possible
values, or could there be "tick", "cross", "blank" ? Personally I would use
Y or y for one value and blank for the other if there are only two values,
and avoid any Excel "boolean value" formatting.

You can do this in several possible ways but the most straightforward is
probably to have an IF field such as

{ IF "{ MERGEFIELD Student1 }" = "Y" "<checked box character>" "<unchecked
box character>" }

Then instead of <checked box character> etc. select the appropriate
character from a character set such as Wingdings and insert it. Also, both
pairs of {} have to be the special field codes you can enter using ctrl-F9.
You may also need to do some formatting to ensure that the Wingdings
characters are not chaged to another font when you merge, but let's leave
that for now.

If necessary you can do it in Word but it's a lot more tedious.

Peter Jamieson