custom sort of the memberlist

[banjolawyer]

The hyperlink for listing members by a particular field is, for example

quote:
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http://xxx/forums/memberlist.php?s=&what=field1
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I have added three custom fields to my user table, and will display those on the memberlist. (For example, firstname, lastname, graduationyear)

I would like rewrite the hyperlink for the "members" button, so that, when clicked, the resulting list is sorted by
1st - graduationyear
2nd - lastname
3rd - firstname

Can anyone tell me what my hyperlink should look like?