Regression with constraints

[steva]

I want to run a linear regression R=b1F1+b2F2+b3F3+b4F4+b5F5+e
with the following constraints:
a) The coefficients to have only values between 0 and 1. 0<bk<1
b) The sum of the coefficients must equal 1 Σbk=1
I would like to ask you if this problem is possible to be solved with excel and the Solver

Thank you in advance