I bet someone else has beaten me to this, but you can combine the strips of parchment using meta functions
actiontryapplyitem[wobjectfindininventorybytemplatetype[1], wobjectfindininventorybytemplatetype[1]]
you can find the proper templatetype number by selecting the strips of parchment and typing this command
/vt mexec wobjectgettemplatetype[wobjectgetselection[]]