While my "solution" works in our situation, it is essentially a crude hard-coded "hack" that would be very time-consuming to effect on a large scale, but the core principal of using JS to filter selections at the PRE-PRODUCT-INFO stage may be workable. It works on the principle of each checkbox having a numerical value. When selected, the SUM of the selected values is calculated, and if the SUM is equal to a certain total, the ONCLICK directs to a product URL. If the SUM does not equal a stated URL onclick value, the default is an alert message. Using the principal of binary exponential incrementation (1, 2, 4, 8, 16, 32, 64, 128, 256, 512 ...) the SUM of values will always be unique to valid combinations of checkbox selections... EG: We don't want a URL for a SUM that equals "3" - because 1, and 2, are mutually exclusive products. But 1 and 4 can be combined, giving a SUM of 5, so we say if the SUM is 5, then direct the visitor to the URL associated with SUM = 5. Similarly, 4 and 8 are mutually exclusive, so a SUM of 12 will throw the alert, as will SUM = 5, 6, 7, 9, and so on...
JSWEB's product "drill-down" search is not restricted to three "levels" as per my example shown
HERE.
It can be configured to provide as many sub-levels as you need.