I didn't realize you had more than 2 targets. The programmer chip will output addresses 0-7 on pins 3, 4 and 5.
Instead of the single 74LV4053 that I've drawn, you could use two of the MC74HC4052A for a 1x4 mux controlled by pins 3/4 of the programmer.
PIN: 5 4 3
0 0 0 0
1 0 0 1
2 0 1 0
3 0 1 1
4 1 0 0
5 1 0 1
6 1 1 0
7 1 1 1
Note the serial resistance on the MCLR lines (R99, R101). The purpose of these is to allow a high-voltage programming cycle from a normal ICSP connector to any single chip. If you don't have resistance, the low-voltage method still works from the programmer chip, but the mux chip won't allow Vpp above Vdd for normal programming.
I also think it's a good idea to have steering resistors on all the pins that will float when not connected through the mux. On my schematic, these are resistors R2, R5, R6, R7, R69, R72.
Is this enough info? I can draw it if needed, but it will be probably be a day or so before I get to it.