Yes! For custom fields that have the attribute Link values to URL, you can define a URL template that will be used to add links to custom field values. In order to use this feature, please specify a fixed base URL and use the following variables for replacement:
%value% for the custom field value
%id% for the numerical ID of the object for which the field is set
%project_id% for the numerical ID of the current project
%project_identifier% for the alphanumeric identifier of the current project
%m1%, %m2%, etc. for the capturing groups of an optionally specified regular expression
For example, if you use https://example.com/customers/%value%, the values of your custom field will be linked accordingly. If the value is set as Appleseed, the resulting URL will be https://example.com/customers/Appleseed.