Spare disk requirement

I have 9 enclosures and 9 dg with a spare in each dg. Do I need a spare in each dg?

In other words, can a spare from one dg be used by another dg in case of a disk failure?

backup@yorkDD# storage show tier active
Active tier details:
Disk Disks Count Disk Additional
Group Size Information
------- ------------------------------------ ----- -------- -----------
dg1 2.1-2.14 14 2.7 TiB
dg3 3.1-3.10, 3.12-3.15 14 2.7 TiB
dg4 4.1-4.14 14 2.7 TiB
dg6 5.1-5.14 14 2.7 TiB
dg5 6.1-6.8, 6.10-6.15 14 2.7 TiB
dg2 7.1-7.13, 7.15 14 2.7 TiB
dg7 8.1-8.9, 8.11-8.15 14 2.7 TiB                 -no spare for this dg, currently
dg8 9.1-9.14 14 2.7 TiB