I didn't play FFXI for long to use macro but I think <stpt> can be accomplished by <stpc>... try it and let me know.
Targeting Placeholders
Placeholder Description
<t> Displays current target name.
<me> Displays your character's name.
<0> Party Member 0. Displays your character's name.
<1> Party Member 1. Displays name of first party member in list.
<2> Party Member 2. Displays name of second party member in list.
<3> Party Member 3. Displays name of third party member in list.
<4> Party Member 4. Displays name of fourth party member in list.
<5> Party Member 5. Displays name of fifth party member in list.
<6> Party Member 6. Displays name of sixth party member in list.
<7> Party Member 7. Displays name of seventh party member in list.
<st> Subtarget.
<stpc> Displays available PC subtargets.
<stnpc> Displays available NPC subtargets.
<stenemy> Displays available engageable enemy subtargets.
<stenmity> Displays available engaged enemy subtargets.
<stparty> Displays available party member subtargets.
<lastat> Displays the last enemy that attacked you.