How to connect devices in a different IP block to my ICX 7450 stack?

[bllhncl]

Hi everyone, I have 6 ICX 7450 switches running in stack mode and currently in switching (L2/SPS) mode. My existing network is on the 10.10.10.x subnet. I need to add 4 new devices with IP addresses in the 169.254.1.x subnet. These devices cannot have their IPs changed, but they need to communicate with a server at 10.10.10.1. Since the switches are currently in L2 mode, I cannot create VLAN interfaces (VEs), so inter-VLAN routing is not possible. My question: Do I need to switch the stack to L3 mode (SPR) to make these two IP blocks communicate? Or is there a way to do this while staying in L2 mode? Any advice or recommendations would be appreciated. Thank you!