conditional lookups?

[Getchi]

I need to populate fields in a database based on a value in a different database (the master d/:.

So, in the master d/b, all the records with a value of X in the category field would populate certain fields in the other database; values of Y in the master d/b would populate other fields, and so on.

I'm new to FM, and the lookups I've done in the past were more straightforward because there was a common field between the databases. For this instance, I think I need to do a lookup based on an IF,THEN statement. Is this possible? Thanks!