Interfacing 2 LAN’s for Internet Access

Hi

I currently have a small LAN consisting of a wireless router and 4 devices.

The builidng I live in has a separate lan with a DHCP that provides internet access.

I need access to the internet while maintaining my internal network for file sharing.

Is it possible to route internet traffic from this second lan without assigning my devices to its DHCP? I am currently using static IP for my home network 192.168.0.2 etc..and the internet access router is on 192.168.112.1.

I cannot alter the internet router as it belongs to the building.

Can I use a default gateway on my own router for this purpose?

Thanks

Ralph