Maintaining integration rules in separate rulesets helps in reusability of those rules in different applications. This improves the maintainability as well.
For example, You can create Org level, Div level integration rulesets and use them according to the layer and scope of the integration rules. You can group all the organization level integration level rulesets into OrgInt ruleset.
If the number of integration rules are very high then you can think of dividing them or grouping them into separate rulesets.