Use an If function to result in more then one answer
 

Is it possible if you had this (see below, tab 2) on one tab to have another
tab that has a cell that would reference what is in row A and result in row
B. Sometimes row B will be the same for each group of what's in row A and
sometimes it will be different. So, say it would say if I would put a
formula in row D to reference row C to look up on different tab row A to get
the answer(s) from row B.

tab 1
C D
12345 Chicago
67891 Chicago, Denver

tab 2
A B
1 12345 Chicago
2 12345 Chicago
3 12345 Chicago
4 67891 Denver
5 67891 Denver
6 67891 Chicago

HOpe all that made sense.

THanks in advance for the help.