I have not looked at the new types much, but a brute force method of only checking certain type instances would be to add a check interval indicator to each type. do the foreach in thing and only do the processing for the ones that match the current check.
Below is really psuedocode...
Below is really psuedocode...
itemstocheck = 3 For Local currentObj:MyType = EachIn typeList if currentobj.checkindicator = itemstocheck then 'Do something with currentObj end if Next