It's possible, but we'd need to know more about your database structure.
Are all thse addresses entered into the same table?
Windows are opened and closed as needed by user actions or scripts. It sounds like you really mean that you have 4 layouts rather than 4 windows. If each of these layouts refer to a different table, then it is very likely that you need to use import records to combine the data from three of these tables with the data already in the fourth. How easy that will be to do, depends on what you have set up in your database file. (You might have many different layouts, scripts and value lists to update. The fields in one table may not perfectly align with fields in another.)
You are right, I have four different layouts. They are all addresses lists for different mailings we do. They are updated regularly and so far the only way for us to avoid duplicates between mailings are to search in each window. If I would import the files altogether would I have to do that each time I wanted the combined list? I would be willing to redo the layout completely if it would be easier to solve this problem. Thanks so much for your advice!
I suggest that you import the data until all of it is in one table, then discard the other three tables. You'll need to think this through before you actually do it. Here are some questions that you'll need to consider:
What makes each table different? (You may need to add a field or two where you enter data to identify the "list" to which a given address belongs, you may even need a related table or a check box field so that you can assign one address to multiple "lists".)
What layouts, relationships and scripts refer to each table? You may need to update and modify these accordingly to use the new table.
Making changes in a copy and testing the results would be a good idea.
Once you have all these records in one table, it's fairly easy to find and remove most duplicates as well as to prevent them in the future.
Thank you! I think you hit it right on with combining them and adding other fields to specify the relationship. I will work on that! Thanks again for your help!