Need help with Bandwidth Prioritization

Hi,

I am brand new to RouterOS and have been muddling through the best I can.
My basic config:
RouterBoard 450G
I have 2 Wan Interfaces, a T-1 and a Bonded ADSL link
2 Inside interfaces - my LAN and a Wireless LAN that’s isolated from the Wired LAN
I have POP, SMTP and VPN traffic using the T-1, everything else is using the ADSL
What I need to do:
Set up a single group (Company president and IT Staff - 4 IP addresses) that would get bandwidth priority when accessing the WAN - ADSL Link, upto 60% of capacity.
Everybody else can fight over the rest.
There’s just too much info out there for me to decipher it all, so if somebody can provide me with a step-by-step process for accomplishing this, I would appreciate it.

TIA.