I know this can be done without using I2C protocol. I found a device that uses two PICs with one LCD just don't know how it's done in software.
Lets call the PIC connected to the LCD the slave and other master

I see that pins RB0-RB3 are connected from slave PIC to the master(the only interconnections) and RA0-RA3 pins of slave are connected to data lines of LCD. Additionally, the slave PIC uses all three control lines (RW, E, RS). Maybe using enable pin to multiplex data from both PICs? I'm sure there are many cases when using multiple PICs with a single display would be desirable. I really don't want to dedicate two LCD displays for each axes.

I appreciate the responses so far.

Chris