Consolidating contacts.

I'm in the process of designing and creating a database to keep track of
people, much like a contacts database, but a little bit more complex.
Currently I have it planned so that there is a students table and an agent
table. Ultimately I need to keep track of emails from Outlook through a
linked table containing the emails. (So I'm filing emails digitally rather
than printing them off.)

My question is if it is possible to consolidate the agents table with the
students table.
The students table contains a lot more information than the agent table
So I was not sure if it would be practical to combine the two directly and
have many of the fields (those that are agents) end up remaining null.
Any help would be appreciated. Please let me know if any clarification is
needed.

Student table fields are as follows:
StudentID (autonumber)
AgencyBranch
LastName
FirstName
DOB
PermanentAddress
PermanentTelephone
Mobile
FaxNumber
E-Mail
ParentE-mail
CountryOfCitizenship
AlternateAddress
AlternateTelephone
DateCompleteApplicationReceived
ApplicationReceivedFromAgency
ApplicationReceivedFromStudent
Photo
StudentType
Session/SemesterOfInterest
Session/SemesterofInitialEnrollment
IDNumber

The Agents table contains the following fields:
ContactID_AN
ContactType
AgencyBranch
LastName
FirstName
PhoneNumber
FaxNumber
MobileNumber
E-mail
Photo