bridging & nat ing

RouterOS General
1

possibilities:

i need mikrotik to do these 5 things:
cache
bridge
nat
bandwidth control
firewall

now i know i can make it do them all, but i am having trouble getting it to do both bridging and nating on the same interfaces(2 nics) is this possible?

2

i want the final layout to look like this

[[internet router]]------[mikrotik]-----[switch]------[[network]]
****internet ipinternet ip + 10.1.50.x + 10.1.100.x

if that helps?