Below is the example of ulimits addition for specific user (oracle) & specific group (sapsys)

[root@testserver ~]# cat /etc/security/limits.d/saplimits.conf
oracle soft nofile 10240
oracle hard nofile 65536
oracle soft nproc 32768
oracle hard nproc 65536
oracle soft stack 10240
oracle hard stack 10240
@sapsys soft nproc unlimited
@sapsys hard nofile 32800
@sapsys soft nofile 32800
@dba hard nofile 66536
@dba soft nofile 66536
* – nofile 8192
* – core unlimited
* soft memlock 18721890
* hard memlock 21602181
[root@testserver ~]#