unable to isolate the branches after svn import

we are trying to import from SVN and create a component that contains multiple branch versions.

here is the scenario

component 1 - includes 10.16 and 11.4 branches.
create the stream and import from the top level folder called branches, sub folders are 10.16 and 11.4 etc.
Called the stream import stream
Create Stream 10.16 from component imported - need to specify 10.16 folder only and you cannot.

scenario 2

component 1 - includes 10.16 and 11.4 branches
process is create stream 10.16 importing from 10.16 branch in SVN. put down a baseline
process is create stream 11.4 importing from 11.4 branch in SVN into same component put down a baseline
we can process in individual streams now we have deliver from 10.16 stream to 11.4. Unable to do so it will require accepting all changes for 11.4 code base into the 10.16 workspace.

How do we import svn code base 1st time and support parallel development of 3 base versions v9, v10 and v11 of our codebase that is currently branched in single svn repository. So we can merge forward changes as needed.
example fix in v9 need to merge forward to v10 and v11. Any ideas or help would be appreciated.

Do we use the patch feature?