How do I float the 89LV51 pins for programming external flash memory on an ICT tester?

I want to use external flash memory for my program. The same memory is used to store configuration data for an FPGA. The configuration data for this FPGA is transferred by a CPLD device. All devices share the same address/data bus.

When the CPLD addresses the flash memory, the 89lv51 should float its pins. These pins should also float when the in-circuit-tester drives these pins for programming the flash device.