Tagging tree filter question

Hi

If i have something like this

<$list filter ="[tags[TableOfContents
]] :filter[get[field1]compare:string:gt[A]] :and[get[field3]sum[]]" variable = "sumfield3">

which goes through every tiddler tagged with “TableOfContents” ,then does a string check on field1 , then if it is successful it sums the numeric values stored in field3 for all matching tiddlers

Now if i want to do the same check . but not only for tiddlers tagged with TableOfContents , but also for all tiddlers tagged with the current tiddler using taggingtree filter, how do i take the original filter(stored in a variable) and incorporate it with a new filter to run on each entry/tiddler in the tree

<$list filter="[<currentTiddler>taggingtree[]<sumfield3>]">  ??

or even simpler what if i just use tagging[] instead of taggingtree[] just to get the first tiddler in the tree,generally speaking how do i combing filters like that ?

Thank you