You can connect all D0s from 4(or more) 74373 in parallel to, say, P1.0 .. all D1s to P1.2 .. all D7s to P1.7 ..
Then you need to control the /LE pins; you can hook them up to 4 separate microcontorller pins, say, P2.0, P2.1, P2.3 and P2.4 ..
To output data on the 74373(1) set required data on PORT1 and make H-L-H transistion on P2.0 to latch the data in 74373(1) ..
If you make similar transiston on P2.1 you will latch data to 74373(2) .. and so on ..
Of course, the /OE pins of all 74373 have to be connected to 0V to enable outputs ..
Regards,
IanP