How can I optimize topology of different parts of a model separately?

Hi, for my projekt I need to optimise topology of different parts of my model separately. As shown in picture I need to optimize the topology of red ring completely normal and then I want to have an lattice optimisation on the blue one. Bcs and loads are defined. Where I got stuck was the assigning of constraints and limitation for the optimisation and then doing it in 2 steps as explained separately. 

The constraints and limitations for my topology optimisation are:

1.radial deflection less than 10%

2. torsional deflection less than 0.5 degree angle of twist

3.  axial deflection less than 2% the axial length

the goal of optimisation is to minimise the mass of the model. The schematics of loads and are shown in the second picture. 

Thanks for helps and guides