Open vented hot water cylinder with secondary return and shower pumps?

[londplumb]

Wanted to get some advice. I am looking to install secondary return pump to open vented cylinder as it has a long run to two wash hand basins that are supplied from side tapping of the hot water cylinder. What this house also has are 3 bathrooms that have baths and showers which have fancy taps with integrated pumps for example below baths.
What i wanted to know is as I will install a pump on existing run from basins to cylinder and then take another supply pipe from top of the cylinder to those wash had basins to create a loop. Is this allowed? or it might have some kind of negative affect on shower pumps or cylinder? 🙂

 

[ShaunCorbs]

 

[londplumb]

Thank you for the diagram. What about if there couple more pipes tee'd off from top of the cylinder pipe with shower pumps installed on those runs would that work?