Further narrowing Value list results in portal

I am new to Filemaker and developing a document manager in FM13. I have spent a lot of time trying to search this forum and others to find a solution but, probably due to my ignorance, I have not found (or just missed) anything that has been able to move me towards a viable working solution. I have a master list of keywords that I am using with the intent of simplifying navigation instead of using a bunch of cascading portals or drop downs. This approach seems to be the base of my issue.

From the image, the portal on the left side is the keyword master list based on the demo by 1-More-Thing, which is populated using executeSQL. Initially, I tried to setup value lists to limit the results from the master keyword list. In the image, the dropdown shown for the TAGS field is correct as all displayed items are associated with selected portal record. However, I need to further narrow the displayed options to just show the items identified as "Tag #" and exclude the rest. In my attempt to narrow the value field, I created a calculation field (Cat) that populated with main category type associated with the keyword. Therefore the keyword numeric value associated with keyword "TAG #1" would populate with the main category value of "TAG". I then set the relation between "Join Tag" and "Data for Main Library" as

join tag::_keyword = data from main library::ID
and
join tag::cat = data from main library::basecat

however this only seemed to lockup the program

As an alternative I tried to use the ExecuteSQL function in a calculation field in the MAIN LIBRARY to populate each field for each record except TITLE. The search criteria was built using SQLExplorer. This provided the desired results (as shown in the field contents in the image) but the response time for interacting with the interface slowed to 4-5 seconds or more to respond to a mouse click or to simply scroll through the main portal. There are about 2500 sample records in the data base. It is expected that there could eventually be 80,000 or more in the working database

Due to the apparent slowness from the SQL executions, I am back to further limiting the value lists though I open to suggestions on overcoming this slowdown issue.

Any suggestions on further limiting the value lists within the main portal would be greatly appreciated.

Thank you