If you're asking if you need three separate Smart Campaigns, I'm not 100% sure since I'm not exactly sure what you mean when you say "I want to add users from previous campain activity."
If the information you're using to determine which Stream in users will fall into is an attribute on their record (i.e., engagement in a previous program marks them a Top, Middle or Bottom in a field on their contact record), you can use the Add Choice function to add everyone to all three streams in a single Smart Campaign.
If the way you're qualifying who goes into what list has to do with activity or membership in previous campaigns, you will need a Smart List per stream. Be careful when setting these up as well so there isn't overlap and you're getting everyone into the correct stream!
Example of add choice:
Hi Michael O'Donnell ,
I think as long as your criteria is being met, the method suggested by Chris will work. For example
Activity X - List 1 (Top Stream)
Activity Y - List 2 (Middle Stream)
Activity Z - List 3 (Bottom Stream)
In your case since the activity is not being recorded in Marketo, the primary challenge for you would be to segregate the activities and add leads with respective activities into lists. Once this is done, you can call those lists and them move them into streams as suggested above.
Best Always,
Karan Hari
Trust you are doing great! 
Just wanted to circle back and check if your query was resolved. Kindly let us know in case of any further queries. Would be glad to help. Also, in case either of the above answers has already resolved query, request you to kindly mark it as correct so that the thread reflects as "Answered", which aids in future searches.
Best Always,
Karan Hari
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