3internet 3tunnel and 3local

hi
i have a question

i have 3 internet on wlan1,wlan2 and wlan3
and 3 separately vpn account for tunnel
ether1,ether2 and ether3 is 3 separately local

how can i set interface for anyone l2tp-client?
example :

ether1–>wlan1–>l2tp1–>internet
ether1–>wlan2–>l2tp2–>internet
ether1–>wlan3–>l2tp3–>internet

how can i set that?

It is not clear what exactly you need. If you need load balancing, then take a look at this article:
http://wiki.mikrotik.com/wiki/PCC