How to setup pip to download from mirror repository by default?

using pip config, on user or global level. I have /etc/pip.conf configured like this:

[global]
index=https://my-company/nexus/repository/pypi-group/pypi
index-url=https://my-company/nexus/repository/pypi-group/simple
trusted-host=my-company

but you can configure this using pip config on user or global level, something like:

pip config --user set global.index https://my-company/nexus/repository/pypi-group/pypi
pip config --user set global.index-url https://my-company/nexus/repository/pypi-group/simple
pip config --user set global.trusted-host my-company

#NOTES

• --index-url is used by pip install
• --index is used by pip search