Filter Combo Box by Login ID

Our company has about 5 different computers on our Network that all have been
using their own copy of an Access db. I thought this would be fine as I like
that they each only have access to their own records which are relevant to
them. This is, however, creating a difficulty for me as far as updating the
db or fixing any errors. I find I have to go through and do it over and over
5 times. I've read up on splitting the database but want to know if I were
to create a login form for each appraiser could I then filter the records and
combo boxes by their login?

Also, I'm a little confused about if this will help with my programming
issues since the forms and code all seem to go on the front-end which would
be loaded on each computer, right? Would I still have to go and change the
code on each computer??

Thanks so much for any help with this!

Pamela