If I understand well, you would like to defer some subscriptions, so that 20 items are subscribed to immediately and the remaining 148 items are subscribed to in the background.
There is no facility by our library for this task; it must entirely be done through custom code, by separating the items in multiple tables and governing the timing of the various "addTable" calls.
Note that the cells on the page should be assigned the "table" attributes accordingly. After all subscriptions are done, nothing should reveal that the cells pertain to different tables.

Consider that, in case of connection problems, after a successful connection recovery, the library will try to restore all subscriptions and in this case the requests will be issued alltogether.