Hi, im setting up a tp link deco x20 (4 units for 3 floors.

 In the first floor there is my router/modem from the isp. 

There are 2 points prepared for each floor 1A 1B , 2A 2B , and 3A 3B which means it supports 6 deco units. 

I plan to install the main deco on 1A , receiving from isp modem . In the 2nd floor a 5 port switch connects 2A and 2B and ethernet from 3A  to 1A.

There is a cable installed on the building to connect point a to b , a to a on other floors , but not b to b other floors. 

Is it possible to use is a switch in that manner?