You could insert the email addresses as plain text, then use a macro like the following to convert them (and any web addresses) to clickable hyperlinks post-merge.
Code:
Sub MakeLinks()
Application.ScreenUpdating = False
With ActiveDocument
With .Range
With .Find
.ClearFormatting
.Replacement.ClearFormatting
.Text = "<[0-9A-ÿ.\-]{1,}\@[0-9A-ÿ\-.]{1,}"
.Replacement.Text = ""
.Forward = True
.Wrap = wdFindStop
.Format = False
.MatchWildcards = True
.Execute
End With
Do While .Find.Found
.Duplicate.AutoFormat
.Collapse wdCollapseEnd
.Find.Execute
Loop
End With
With .Range
With .Find
.Text = "http://[! ]{1,}"
.Execute
End With
Do While .Find.Found
.Duplicate.AutoFormat
.Collapse wdCollapseEnd
.Find.Execute
Loop
End With
End With
Application.ScreenUpdating = True
End Sub
Depending on your system's regional settings, you may need to replace the three {,} expressions in the code with {;}.