Does anyone here has any experience in setting up a family portfolio?

I'm thinking of setting up a family portfolio with them providing a lump sum at the start followed by monthly contribution. The amount provided by them will be based on what they can afford but must be recurring on a monthly basis.

Are there any particular things I need to take note of? What would be the best way to determine the individual returns (IRR?)? And what would be the best way to enjoy the returns (dividend payout)?