I have read the data sheet and can't seem to find anything. I noticed some other chips have a SSPCON2 register, bit 7 looks like what I need.

GCEN: General Call Enable bit (In I2C Slave mode only)
1 = Enable interrupt when a general call address (0000h) is received in the SSPSR
0 = General call address disabled

The 16F819 does not have this register. I am stuck with the 18 pin interal osc with some analogs and I2C form, but I would really prefer getting the 16F819 working with an interupt. I have an 16F88, but that also does not have the SSPCON2 register either...