Try this ... create a global text field called From and a global text field called To. This will hold your beginning and ending phrases or words. Then create a calculation ( result is text) with:
Let ( [
start = Position ( Data ; From ; 1 ; 1 ) ;
end = Position ( Data ; To ; 1 ; 1 ) + Length ( To ) + 1
Middle ( Data ; start ; end - start )
You can then set the calculation on your layout as well next to the two globals (label the calc 'copy contents' so User knows and set field behavior (data tab) as 'select entire contents upon entry.' When you click into the field, it will insert the contents onto your clipboard. highlight the entire result so you can copy it onto your clipboard. If you wish you can turn off entry to the field and attach script so that clicking the field automatically copies to clipboard (script-step Copy) or even use script trigger.