I have a custom object which has a list of products, country field and checkbox- inactive.

Use case: 
When I create an opportunity and add OpportunityLineItem, The line item should compare with the products field from the custom object.
Also, the Opportunity should look at Bill to country from the account attached and compare with the country field from the custom object.
And if the record matches and the "Inactive" checkbox from the custom object is true, then it should throw an error and not allow to save the opportunity.

For example,
Custom object:
Product: Pencil
Country: Mexico
Inavtive: True

Opportunity:
OpportunityLineItem: Pencil
Account - Bill to Country: Mexico
ERROR FLAG

Can this be achievable ? If so, can i receive some help on building the trigger ?

Thank you in advance.