Data input timing

Hi,
There will be 3x sets of DATA inputting a PIC. 2x from radio HSERIN sources and 1x from SPI.

1x HSERIN will be timed at 1/sec (Using an INTERRUPT)
1x HSERIN will be timed randomly a few times/sec (Using an INTERRUPT)
1x SPI will be timed randomly a few time/sec (Just implementing)

Assume for now that they are all as important.
Sometimes there will be no DATA.

Which is the best way to look at this? At the moment the 2x HSERINs are TOGGLING between them, and rely on DATA being present,...

Data input timing