instead of using HAVING you should be using WHERE because you aren't using a group by clause. so it should look something like this
SELECT Alum.LastName, Alum.FirstName, Alum.Street, Alum.City, Alum.State, Alum.Zipcode, Alum.Country, Alum.Phone, Alum.Email, Alum.Employer, Alum.Title, Alum.WhenGraduated, Alum.DateUpdated, Alum.InitiateNumber, Alum.CompName
FROM Alum
GROUP BY Alum.LastName, Alum.FirstName, Alum.Street, Alum.City, Alum.State, Alum.Zipcode, Alum.Country, Alum.Phone, Alum.Email, Alum.Employer, Alum.Title, Alum.WhenGraduated, Alum.DateUpdated, Alum.InitiateNumber, Alum.CompName
WHERE Alum.InitiateNumber = 1;
the '1' is just the example number i used. if you want it related to a specific number you'll have to tell me what language you are using to display the data. hope that helps