how i can use multi mikrotik PPPOE server in the same network

you could create two address list L1 and L1.
To address list L1 insert client ip's belonging to isp1, to address list L2 insert client ip's belonging to isp2 (this can be done also using radius).
Then you must have two mangle rules where you add a routing mark R1 to L1 address and R2 to L2 addresses.
Finally add two default gateways (one for each isp) filtering by routing mark.