How do we select specific bits from a bus?

Hello all, I am new here and I have a problem using the block diagram in quartus II with cyclone III.

So I am trying to select specific bits from a bus, and have no luck yet.

I know how I can select a bits to connect to a Node but I am not sure how I do this in Bus with my set up now.

So I have a LPM_ShiftReg with 40 bits as a data input.

bit [39..28], [15..0] of this data will be a constant (using LPM_constant)

and I need to input bit [27..18].

On the other side of my block diagram, I have another LPM_shiftReg which inputs ****fIn and output Q as data bus with 16bits (15..0).

Now I need to take the bits [11..0] of this second shift register to feed back into [27..18] of first shiftregister.

Can someone tell me how I can achieve this please?

(I am not familiar with VHDL or verilog.. and it would be really appreciated if you tell me how I can do this with block diagram.)

Thank you!