RXTX20 firmware rewrite

I have a project made up of 2 parts, the TX and the RX. We are using radio’s to communicate between the TX and RX which communicate serially, one way. The TX comprises of 20 momentary push buttons arranged in a matrix and 6 singular momentary buttons. The TX has an UP and DOWN button which is used to select a channel number between 1 and 128. The 20 momentary buttons when pressed selects the corresponding 1 to 20 outputs on the RX The TX uses an OLED display and the RX a LCD display. The RX has 20 outputs as well as a UP and DOWN which selects the channel number. Only when the RX channel number is the same as the TX channel number will the outputs work when the 1-20 buttons on the TX are pressed. I have firmware (being used in another project) already in use with certain features I would like to retain. Both TX and RX are using the PIC16F886 The RX has the PIC16F886 connected to a 20 bit serial input latched source driver - A6812 I require someone to write the firmware for both the TX and RX devices. I can supply diagrams and schematics.