My regex skills are not very good and recently a new data element has thrown my parser into a loop

Take the following string

"+USER=Bob Smith-GROUP=Admin+FUNCTION=Read/FUNCTION=Write"

Previously I had the following for my regex : [+\\-/]

Which would turn the result into

USER=Bob Smith
GROUP=Admin
FUNCTION=Read
FUNCTION=Write
FUNCTION=Read

But now I have values with dashes in them which is causing bad output

New string looks like "+USER=Bob Smith-GROUP=Admin+FUNCTION=Read/FUNCTION=Write/FUNCTION=Read-Write"

Which gives me the following result , and breaks the key = value structure.

USER=Bob Smith
GROUP=Admin
FUNCTION=Read
FUNCTION=Write
FUNCTION=Read
Write

Can someone help me formulate a valid regex for handling this or point me to some key / value examples. Basically I need to be able to handle + - / signs in order to get combinations.