Hello!
So, I've set portb of the PICAXE28X1 to all outputs pin b.0 to b.3 is connected to a 4511 7 seg decoder (which is then connected to a 7 segment display) and b.4 to b.7 is connected to another 7 seg decoder. However, I'm not sure how I would separately make them show different numbers. Any help/advise would be appreciated.
Thanks!

 

Post a schematic so we can talk intelligently about your circuit.

 

if port b is bit addressable, then you can write specific bits without engaging other bits.

similar approach is to see if port b can be addressed in halfs like some timers and counters. timers are often split into two halfs, the higher 4 bits and the lower 4 bits. the user than can load whatever they need into specific half of the timer and leave the other half untouched. is port b such device where you can engage one half of the bits without engaging other half of bits?

you could just manually write to the whole port making sure you do not overwrite the bits that you want to remain unchanged.

so far it sound like you did not think through what you want to do. which is definition of bad design. time to open and read datasheet