How to ensure that values between ones is less than or equal to specific number?

I have these row vectors:

T = 1:11

C = T(1)

a = T(2:6)

b = T(7:11)

Da = [10 12 8 10 7]; % these vaules are corresponding to a values

Db = [10 9 8 10 7]; % theses vales are corresponding to b vales.

TD = 40

r = [1 2 3 7 8 1 4 8 9 1 5 6 10 11 1]; % r is a random permutation vector/ matrix consists of a and b values( a should always be followed by b in sequenc) after inserting ones which is C.

How to create a loop to ensure that the Da valuse, which are corresponding to a values, are less than or equel to TD(40) between each ones.

Same for Db, which are corresponding to b values, they also should be less or equel to TD(40) between each ones.