SendObject To More Than One Email Address

The code below works for the one email address "Quality Assurance"...but I want to add more email values to SendObject command.
If I do this: stEmail = Me.Quality_Assurance_Authorizer.Column(1) And Me.Engineering_Authorizer.Column(1)..... I get a Runtime error '13' Type mismatch. Is there another way of including a series of email values into the SendObject code below? The reason I'm using the value of the column is that sometimes the value may be null if that department doesnt need to be emailed. Thanks for any help.


Private Sub cmdPCAuthSend_Click()

Dim stDocName As String
Dim stEmail As String

stDocName = "rptPCAuthReq"
stEmail = Me.Quality_Assurance_Authorizer.Column(1)
DoCmd.SendObject acSendReport, stDocName, "SnapshotFormat(*.snp)", stEmail, , , "PCA Authorization Request", "Please review this product change and authorize when appropriate."

Exit_cmdPCAuthSend_Click:
Exit Sub

End Sub