As a followup to my original question, I also need to "disconnect" the power (+5.0 volts and +3.3 volts) to their respective pin on the two 8051 processors in use.

Again, I don't have the option to use some sort of switchable (onoff) voltage regulator. I need to disconnect the power from the two ICS via some device.

Again, normally, these connections would be closed (5 and 3.3 applied directly to the power pins).

I assume a simple transistor like device (or MUX chip) wouldn't do the job here. What is the recommended solution for this?

Thanks
Mika