If I understand correctly, you wish to have the videowall act as separate screens?
With the videowall daisy chained, its not possible to send different videofeeds per monitor.
options:
1) Of course you can "cheat" by making custom content that's segmented (e.g. a single video in which each corner shows a different video in case of a 2×2 Vwall)
but this would require a lot of custom content creation which can be very expensive in the long run.
2) 4 separate Sbb's, 1 for each monitor, this would require an additional 3 sbb's and mi licenses