Hlookup with Merged cell as look up value

Hopefully someone can help me out on this one. I have a spreadsheet that
looks similar to this:

2/15/2010 3/15/2010 . . .
Site# INV VALUE INV VALUE
1 34 332 40 440
2 47 250 47 250
3 55 476 36 420
Total 136 1058 123 1100


I am trying to use a Hlookup to return both the Totals for both the INV and
Value in a compainon sheet. The date cells are merged over the INV and VAL
Colums so my Hlookup formula only returns the INV value. Anyone know of a
way to have a Hlookup return the value in the right column or another work
around for this problem.