🚀 go-pugleaf

I want to create dictionary style headers and footers but I don't want FM to take the actual text in the first and last paragraphs on each page. I want to supply my own header and footer texts. 

For example: Imagine a page containing the following paragraphs 

AARDVARK.... 
ABACUS.... 
ANT.... 
ASTEROID.... 
BEE... 
BEND... 

I want to create the running header based on the first 3 characters of the first word of the first paragraph together with the first 3 characters of the last paragraph. e.g. 'AAR-BEN'. 

Does anybody have a good idea about how to do this. 

I was hoping that Adobe would give me a function whereby I could acces the *LAST* occurence of a marker on a page in the new FM7, in the same way I can access the first and last occurences of a paragraph tag (<$paratext[+,para]>) 

Any hints/ideas are welcome!