The present specification faces the issues of selecting a right 5G Network Function, NF, instance in scenarios wherein NF instances are considered NF segments that manage different sets of users and wherein NF segmentation is not based on SUPI ranges. To solve these issues, there is provided a new procedure for accessing an NF segment, wherein registration and discovery of the right NF segment is based on a Routing Indicator, and wherein the Routing Indicator, which is received with a Subscription Concealed Identifier (SUCI) identifying a UE, is included in any interaction between 5GC NFs.