Long labels cause problems in merge.

When I set up a mailmerge for labels in WORD, I get good
results as long as the addreses are standard size--three
lines or 4.  As the addresses get longer (5 or 6 lines or
more) WORD vertically centers the text within the label.  
This causes formatting problems.  I often use large size,
shipping style labels (6 to a page) for mailings in which
I insert a logo at the top of the label.

But when the addresses are long, WORD moves the center of
the text block upwards as the number of lines increases,
throwing the formatting off.

Is there a way to make the text in the labels start at
the same vertical position, regardless of how many lines
of text there are?