truncating formulas that point to several worksheets to a few

[wolfpacker]

I cannot figure out how to take this formula which takes values from multiple
worksheets:

=MIN('1'!H6,'2'!H6,'3'!H6,'4'!H6,'5'!H6,'6'!)

and truncate it to ignore worksheets '3' through '6'):

=MIN('1'!H6,'2'!H6)

all while preserving the ability to increment the row # to ultimately copy
the formula throughout a large spreadsheet. I want to update all formulas
such that the #REF! error when worksheets '3' through '6' are deleted.

Thanks for any advice!!