Help With Vinyl Numbering in my script


Can someone help me please just finishing up my script, please?
I understand just a bit of this script so I piece stuff together and it takes me forever to get things to work.
but now I am stuck,
I want only when it is a vinyl release to have my track numbers like this…
A1, A2, A3 … B1, B2, B3
but keep CDs and Digital media normal numbering. Here is my script if someone can just help add the last bit of tagger script it would be greatly appreciated.

$left($if2(%originaldate%,%date%),4) - %album% [$if(%releasecountry%,%releasecountry% - )$if(%label%,%label% - )$if(%catalognumber%,%catalognumber% - )$if(%media%,%media% - ),)
$if($eq($left(%_bitrate%,5),$right(%_bitrate%,5)),CBR $left(%_bitrate%,3),VBR)
$set(_numbr,$div(%_bitrate%,1000)) - $if2($left(%date%,4)
$if($gt(%totaldiscs%,1),][%totaldiscs%%media%,)])/$if($gt(%totaldiscs%,1),%discnumber%-,)$num(%tracknumber%,2)$if(%compilation%, %artistsort% -,) %title%


I could have sworn there was a variable for this, but I just checked the documentation and I can’t find it.