jQuery Grid Plugin - jqGrid

Is there anyway we can reload with filtered data on multiselect dropdown lists  ? We need this solution to be implemented ASAP. I would greatly appreciate if anyone can share the solution.

Eg : I have continents, Countries, States and Cities. I need to show USERS a filtered view when user chooses CONTINENT , I should display ONLY countries in the COUNTRY column  multiselect options and similarly it goes for states. I should not make server side call for each filter.  I am calling the following function from LOADCOMPLETE event of GRID but this is not working for the obvious reason mentioned in this thread.

 

function setSearchSelect(columnName)
{

$("#list").jqGrid('setColProp', columnName, {

editoptions: {
value: buildSearchSelect(getUniqueNames(columnName)),
multiple: true

},

searchoptions: {
sopt: ['eq', 'ne'],
value: buildSearchSelect(getUniqueNames(columnName)),
attr: { multiple: 'multiple', size: 4 },
dataInit: dataInitMultiselect

}
}
);
}