DFD - External Entities & Processes Issue

Hi all,

I am starting to document my online application functionality design by drawing up some DFD's (Contex Level 0, Level I, and Level II), and have come across an issue that I don't really know how to implement it in to the diagrams.

My problem is that as my online application uses user access control permissions, which means certain users can perform certain functions. But there is also the means that certain user groups can perform identical functions - which leads us onto my problem. If I have certain user groups that can perform the same function (such as 'update project data') do I have draw a 'Process' for each user_group that can perform the update on the project - meaning I have to have each user group as a separate 'external entity' that performs this process.

Ideally, what I would like is to have one process to identify the function that can be performed, and then have one generic 'External Entity' (that represents all user groups) accessing this process - is this possible/valid?

Thanks

Tryst