Update single select field option based on the other field selection using automation

[Support Xeleron]

I want to implement automation rule to achieve below:

• Select an option from single select list field A, updates the value of single select list field B
• The value of field is dependent upon the first 3 letters of field A
• There is only one value matching with the prefix(first 3 letter)

[Jack Brickey]

There isn't a means of accomplishing this with automation. Maybe, if using a company managed project you could rethink the solution and leverage a cascading select field.