Noob looking for help with selectors

Noob looking for help with selectors

Hi,
I have a table with a header consisting of colspans.
Now I am looking for a way to select all th-elements having an index smaller than a given one for example 4 with a colSpan attribut greater than 1.
Is this somehow manageable?
I've tried stuff like this but not had any luck so far:

var test = $('thead tr:first th:lt(4)['colSpan!=1'], this);

Any advice would be appreciated.

Thanks.