Is it possible to use two ISP on same BM 3.7 or 3.8 box ?

I want to use the first ISP to provide acceleration proxy for my internal
web site accessed from the internet and the second ISP (DSL) to allow
surfing on the web for internals users surf and GWIA traffic (if possible).

Can you help me ?

I wish to find documentation about this.

Thanks in advance for your help.