Ive got a device on 192.168.1.211 with a static IP that is set on the device that i cant change (dont have the software for the device)

The network range we use at this site is 192.168.81.xxx all other devices are on this network range.

I need the other devices to be able to speak to the device at 192.168.1.211. Is it possible to have an alias for 192.168.1.211 on the 192.168.81.xxx range or bridge them together some how. Or would this be done some other way ?

Which Draytek device?

Perhaps you could create a VLAN/LAN (single port), with a network id of 192.168.1.0 and plug the device into this port. With the Interlan-routing enabled, you might be able to access it this way. The show-stopper could be the default gateway that is configured on the device. If you know what it is, you can configure the Draytek to match. If you don't know what it is, port-mirroring and Wireshark might help you discover it.

Or it may just work