You want to define SLA’s are for each customer separately.
Configuration Guide
Works for JIRA Service Desk Cloud and Server.
This solution will work well if you do not allow public sign up and instead add all customers yourself so you can manage user groups for each new SD customer.
- Create user groups by company (i.e. CompanyA, CompanyB).
Set up SLAs based on reporter of an issue using JQL:
reporter in memberOf(CompanyA)
and
reporter in memberOf(CompanyB)
Alternatively, you could provide "Organization" drop down on issue create screen for user to self select while creating each new issue which organization they belong to. 
Cons to this approach is exposing your full customer list to each Service Desk customer but this may be acceptable in some situations.
Works for JIRA Service Desk Server only.
If you allow public signup to your JIRA Service Desk, you can configure a custom field to capture what company user belongs to. Then use a plugin, one we've used before – JIRA Misc Custom Fields, to extrapolate the company from the user's email address into a separate field which you could call "Company". You can then set up SLAs based on this new "company" field per each customer. Cons: some customers may use generic email address @gmail or @hotmail instead of a company-specific email address.
Listeners, conditional formatting, and calculated fields are currently restricted functions in Cloud. See feature requests below.
Related Feature Request(s)
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