getting count grouped datatable vb around linq

i'm controlling mental roadblock here i'm anticipating i'm blank something obvious.

anyway, assume i have list looks this:

id            lookupvalue         sortorder
============================================
1                               1000
2             b                   2000
3             b                   2000
4             c                   3000
5             c                   4000

i'm perplexing find, controlling linq, places where lookupvalue same, nonetheless arrange method opposite (the id pk database list irrelevant exercise).

i guess easiest proceed organisation lookupvalue sortorder following places where lookupvalue appears some-more twice result.

right now, formula grouped list looks this:

dim keysortpairs = d mydatatable _
            organisation pivotal = d(lookupvalue).tostring(), sortorder = d(sortorder).tostring() _
            organisation _
            name key, sortorder

looking debug output, above formula produces outcome (which correct):

key    sortorder
================
a      1000
b      2000
c      3000
c      4000

to register key's then, i'm looking by law this:

for any opening keysortpairs.where(function(t) t.key.count() > 1)
    'multiple arrange orders!!'
next

in code, however, every opening grouped outcome gets returned. am i blank something, shouldn't count wholly give me entries where key appears some-more once? i assume i'm origination excusable mistake due low-level comfort vb.net, nonetheless i can't figure out -- i've attempted relocating count() where apportionment linq expression, nonetheless gave me same thing.