How overcome restrictions on Technician portal Maintenance Engineer

When I worked on solution for customer I faced a problem as follows.  When we are using Technician portal Maintenance Engineer and we have started to complete Work task assigned to Mechanics (I am a member of that Resource group), but we see that the task can’t  be completed without completion of an additional task by Electrician, we have to create the new task for them. I was trying to use the functionality Additional Work - Request additional work that needs to be done and create Task for Electrician (I don’t belong to that Resource group), but I couldn’t assign this task to Electrician (I was able to assign the task just to the Resource groups that I belong). What can I do in order to overcome this restriction, that would enable me to assign the task to Electrician?