I had a situation where this was needed.
Came up with this:
function onFilterList()
if filterList > 5 then
filterList = filterList + 8
end
zone:setParameter("Filter.ShapeA", filterList)
end
filters = {[0] = "LP24", "LP18", "LP12", "LP6", "BP12", "BP24", "BR12", "BR24"}
defineParameter("filterList", nil, 0, filters, onFilterList)