Hello,
If You are asking whether gateway address 1.1.1.3 can be used by hosts residing on subnet 1.1.1.80/28, the answer is no. 1.1.1.3 is not within 1.1.1.80/28 subnet, period.
You have to change either the additional subnet, or its mask to achieve what You are asking for.
You could play with proxy ARP on irb.1 but proxy ARP is full of non-trivial pitfalls, see my other post.
HTH
Thanks
Alex