Hi

This can easly be done in PBP using the I2CREAD and I2CWRITE commands.
The I2C routines in PBP are software based and can be assigned to almost any pin on the PIC, in your case you could use RC0 - RC7 as 4 seperate I2C interfaces.

The manual expalins alot of the function for this http://pbp3.com/downloads/PBP_Reference_Manual.pdf section 5.33 & 5.34, but I'd be more than happy to answer any specific questions you may have.