Array, Index, Match?

I'm having trouble working this one out.
It may seem redundant but there is a reason behind it.

I have a sheet with; (Sheet1)
A1:C20 - Y/N Boxes
D1:D20 - Text Box (will be numbers listed e.g. 1,2,3,4,5,6)

On a separate sheet i have; (Sheet2)
A1:A20 - Text Box (will be single or pairs of numbers e.g. 1,2 3,4 5,6)
B1:D20 - Y/N Boxes

Basically Sheet 1 will have 'Y' entered into A1:C20 - only one per row i.e. A1 = Y then B1 and C1 will be N (or empty)
Column D will list numbers, same number may be listed in multiple rows;
e.g.
A1 = Y - D1 = 1,2,3,4
B2 = Y - D2 = 3,4,5,6
C3 = Y - D3 = 1,2,5,6
etc

What i want is, when a number is entered into Column A on Sheet 2 for boxes B1:D20 to auto populate based on the data on sheet 1.
e.g.
A1 = 1,2 then B1 & D1 = Y
A2 = 3,4 then B1 & C1 = Y
A3 = 5,6 then C1 & D1 = Y