Is there a reason to create set_pose service in global namespace in EKF node?

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I'm using robot_localization package under melodic to fuse odom, IMU and GPS RTK data. I followed the tutorials and use two EKFs and navsat_transform node.

I was wondering if there is any reason for creating the /set_poseservice and topic subscriber using global node handle: https://github.com/cra-ros-pkg/robot_... ? My problem is that having two EKFs running I cannot use /set_pose service for both of them because only one is available (probably due to naming clash?):

root@2c1c12b2e1b7:~# rosnode info /ekf_se_odom -q
--------------------------------------------------------------------------------
Node [/ekf_se_odom]
 ...    
Services: 
 * /ekf_se_odom/enable
 * /ekf_se_odom/get_loggers
 * /ekf_se_odom/set_logger_level
 * /ekf_se_odom/toggle

root@2c1c12b2e1b7:~# rosnode info /ekf_se_map -q
--------------------------------------------------------------------------------
Node [/ekf_se_map]
...
Services: 
 * /ekf_se_map/enable
 * /ekf_se_map/get_loggers
 * /ekf_se_map/set_logger_level
 * /ekf_se_map/toggle
 * /set_pose

I could use the /set_pose topic for this purpose, but one of the EKFs should get the message with header.frame_id="map" and the other with header.frame_id="odom".

The reason why I want to do it is I'm manually setting datum for navsat_transform after moving some distance to determine heading based on GPS. My IMU does not provide reliable heading after start hence I want to deduce it from short straight line motion and set datum and then I have to reset the EKFs since /set_datum also resets the GPS-based odometry published by navsat_transfrom (which would cause jumps in the ekf_se_map).