Make your post commands of one title go to a new PGC in VMG that calls the 2nd title if a register is set, otherwise return.
For example (using R15 as a free register):
A. Play All links to a new PGC in the VTSM which has 2 lines: (i) Sets R15 = 3072 and (ii) Links to a PGC in VMG that plays the kp 1 title.
B. Make the 1st post command in kp1 that if R15=highlighted button then Jump to VMGM PGC new, resume cell 1.
C. VMGM new PGC simply has a jump to the title PGC of kp2.