How to configure gateway for multiwan configuration on different public ip pool

[hd]

Hello,

Recently we changed service provider. our previous provider used to gave us public IP's in one gateway but the new isp has given public IP pool with different gateway and main static ip in different gateway. see below example ip ranges given by them.

I am confused on how i could setup following configuration. ( IP's numbers are changed for security reasons )

WAN

IP - 185.81.117.14
Sub net - 255.255.255.252
Gateway - 185.81.117.13

Public IP Pool - 185.81.117.96/29
Network - 185.81.117.96
Gateway - 185.81.117.97
Broadcast - 185.81.117.103
Usable - 185.81.117.98 - 185.81.117.102

Can anyone tell me how do i configure them in PFSENSE 2.3.3? Right now we are using gateway directly for one ip only as IP - 185.81.117.14
Sub net - 255.255.255.252  Gateway - 185.81.117.13 (static ip ) and that works but i am not able to configure public ip pool as i don't know how could i setup it in gateway.

ISP is providing us lease line and it directly goes into wan interface of pfsense there is no router involved here.

Thanks for your help :)