changing portals?

i am new to using portals up till last week i avoided them at all cost and a consultant came in and insisted that we used one to compile our phone lists. we have three lists where i work that we use

AMC & ASC (my company)

CUSTOMERS

VENDORS

the consultant said to make one table containing every name and number, then have a value list of the three list options on another table and when you pick a list name it show that list....simple enough made sense...except each list shows different data, the company list has 4 feilds:

name

department

extension

nextel

the customer list shows several more:

builder

subdivison

name

id #

cellphone

officephone

fax

email

and some others

can i set up the portal to when you chose a list name the defined feilds in the portal change so that i don't have a bunch of extra feilds empty on one list and not enough for the other