On CentOS 6, how to let user-created files inherit permissions from their parent directory?

So our servers are set-up like this:
Folder structure

/asic is our grand project's folder, /200T is a subproject of that grand project, and folders right under /200T such as /lbh are each worker's personal directories who are working on the subproject. /asic, /200T, /lbh were all created by root and then had their properties reconfigured by root via chmod -R and chown -R. /asic and /200T are owned by root and belongs to groups asic and 200T respectively, while /lbh is owned by the worker's user account lbh and belongs to group asic.

The idea is that content within /asic and /200T can be seen by all personell working on asic and 200T yet they cannot have write access to these 2 directories-- if they want to create something, they'll have to do that within their own directories (/lbh and the like). When a worker creates something in their own directory, we want other workers of the same sub-project to be able to read that new thing, but not modify it by accident. For example, lbh just created a file testbench.v and a folder /results under /asic/200T/lbh. Another person (glj) on the 200T subproject should be able to read /asic/200T/lbh/testbench.v and /asic/200T/lbh/results but not write into them. If glj wants to modify them, he'll have to copy them to his own directory /asic/200T/glj and then do so.

To achieve the goals above, we need the permissions of directories created by lbh to be drwxr-s--- and files to be rwxr-s--- by default, however the reality looks like this:
Files and folders created by lbh and root

Resulting in each worker being able to write into everyone's own folders and files, which is exactly what we're trying to avoid. The umask of root is 0022, and the umask of normal users is 0002.

My questions:

1. Why are the files created by users (like /lbh) under their personal directories (like lbh) ignoring the drwxr-s--- permission of the personal folder and defaulting to (d)rwxrwsr-x?
2. Is there safe method to let workers create files and folders with (d)rwxr-s--- by default? Asking every user to manually chmod everything every time is too much of a hassle, and I'm worried that changing the default umask value can lead to new surprise issues down the line.

Thanks a lot!

Edit: The folder structure and permission of files created by lbh and root look like this:

[lbh@<machine> lbh]$ ls -al
total 16
drwxr-s---. 4 lbh  200T 4096 Oct  1 02:40 .
drwxr-sr-x. 4 root 200T 4096 Oct  1 02:18 ..
drwxrwsr-x. 2 lbh  200T 4096 Oct  1 02:26 aaa_lbh
drwxr-sr-x. 2 root 200T 4096 Oct  1 02:26 aaa_root
-rw-rw-r--. 1 lbh  200T    0 Oct  1 02:38 file_lbh.txt
-rw-r--r--. 1 root 200T    0 Oct  1 02:40 file_root.txt
[lbh@<machine> lbh]$ pwd
/asic/200T/lbh
[lbh@<machine> lbh]$ cd ..
[lbh@<machine> 200T]$ ls -al
total 16
drwxr-sr-x. 4 root 200T 4096 Oct  1 02:18 .
drwxr-x---. 3 root asic 4096 Oct  1 02:16 ..
drwxr-sr-x. 2 root 200T 4096 Oct  1 02:18 aaa
drwxr-s---. 4 lbh  200T 4096 Oct  1 02:40 lbh
[lbh@<machine> 200T]$ pwd
/asic/200T
[lbh@<machine> 200T]$ 

And getfaclresults of directories and files are as follows:

[lbh@<machine> Desktop]$ getfacl /asic
getfacl: Removing leading '/' from absolute path names
# file: asic
# owner: root
# group: asic
user::rwx
group::r-x
other::---

[lbh@<machine> Desktop]$ getfacl /asic/200T/
getfacl: Removing leading '/' from absolute path names
# file: asic/200T/
# owner: root
# group: 200T
# flags: -s-
user::rwx
group::r-x
other::r-x

[lbh@<machine> Desktop]$ getfacl /asic/200T/lbh
getfacl: Removing leading '/' from absolute path names
# file: asic/200T/lbh
# owner: lbh
# group: 200T
# flags: -s-
user::rwx
group::r-x
other::---

[lbh@<machine> Desktop]$ getfacl /asic/200T/lbh/aaa_lbh/
getfacl: Removing leading '/' from absolute path names
# file: asic/200T/lbh/aaa_lbh/
# owner: lbh
# group: 200T
# flags: -s-
user::rwx
group::rwx
other::r-x

[lbh@<machine> Desktop]$ getfacl /asic/200T/lbh/aaa_root/
getfacl: Removing leading '/' from absolute path names
# file: asic/200T/lbh/aaa_root/
# owner: root
# group: 200T
# flags: -s-
user::rwx
group::r-x
other::r-x

[lbh@<machine> Desktop]$ getfacl /asic/200T/lbh/file_lbh.txt 
getfacl: Removing leading '/' from absolute path names
# file: asic/200T/lbh/file_lbh.txt
# owner: lbh
# group: 200T
user::rw-
group::rw-
other::r--

[lbh@<machine> Desktop]$ getfacl /asic/200T/lbh/file_root.txt 
getfacl: Removing leading '/' from absolute path names
# file: asic/200T/lbh/file_root.txt
# owner: root
# group: 200T
user::rw-
group::r--
other::r--

[lbh@<machine> Desktop]$ touch hello.txt
[lbh@<machine> Desktop]$ mkdir hi 
[lbh@<machine> Desktop]$ ls -al
total 12
drwxr-xr-x.  3 lbh lbh 4096 Oct  9 17:28 .
drwx------. 36 lbh lbh 4096 Oct  9 17:21 ..
-rw-rw-r--.  1 lbh lbh    0 Oct  9 17:27 hello.txt
drwxrwxr-x.  2 lbh lbh 4096 Oct  9 17:28 hi
[lbh@<machine> Desktop]$ getfacl hi
# file: hi
# owner: lbh
# group: lbh
user::rwx
group::rwx
other::r-x

[lbh@<machine> Desktop]$ getfacl hello.txt 
# file: hello.txt
# owner: lbh
# group: lbh
user::rw-
group::rw-
other::r--

[lbh@<machine> Desktop]$