No VBA, Data Validation List, with Custom Formula, cell value can't equal adjacent cell value

[blbat]

Without using VBA, is it possible for me to use a data validation list of "0,5,10" in two columns, "H" and "I", AND in column "I", make it impossible for user to select "10" IF "10" is already entered in column "H"?

 

[blbat]

For anyone else that ever searches for this type of problem....

after bashing around a bit on my own I find This works:

=IF(H2=10,NoTen,INDIRECT(H2))

where "NoTen" is a Named range containing values "0", "5"

Now I need an

=IF(OR

statement to allow for no value in Column "H".

I thought this would work:
datavalidation List in "I2"

=IF(OR(H2=10,H2=""),IF(H2=10,NoTen,INDIRECT(H2)),IF(H2="",PickOne,(H2)))

but I'm having some problems with it. will post back if I solve.