Yes, with stored procedures this is easily achievable, but I cannot use it in scenarios like:

declare @t table (Id int, I1 int, I2 int, I3 int, I4 int, I5 int)

-- insert ...

select Id, dbo.AreEqual(I1, I3, I5), dbo.AreEqual(I1, I2), dbo.AreEqual(I4, I5)

from @t

-- or

select *

from @t

where dbo.AreEqual(I1, I2) and dbo.AreEqual(I4, I5)