Say your company is committed (and don't want to consider not doing this) to sharing/pooling a development team across a handful of business units. What would you setup as concerns/expectations that must be cleared before doing this? For example:

• Need agreement between units on how much actual time (FTE) is allocated to each unit
• Need agreement on scheduling of staff
• need agreement on request procedure if extra time is required by one party
• etc...

Have you been in a situation like this as a manager of one unit destined to use this? If so, what were problems you experienced? What would you have or did implement? Same if you were the manager of the shared team.

Please assume, for discussion, that the people concerned know that you can swap devs in and out on a whim. I don't want to know the disadvantages of this approach; I know them. I want to anticipate issues and know how to mitigate the fallout.