A network node (2200) provides cells serving uplink, UL,and downlink, DL, resources for wireless communications between the network node (2200) and a user equipment node, UE, (2100). The network node (2200) forms (2300) a primary aggregation group of cells that contains a primary cell, PCell, and operates (2302) the UL and DL resources of the PCell in the primary aggregation group to communicate with the UE (2100). The network node (2200) configures (2304) the UE (2100) to connect to a serving cell, and assigns (2306, 2308) the serving cell to a secondary aggregation group of cells. The network node (2200) sets up (2310) the UL and downlink resources of the serving cell as a group PCell in the secondary aggregation group for communication with the UE (2100). Related user equipment and methods by network nodes and user equipment are disclosed.