config join-group vs static IGMP group

[pbarbieri]

What is the difference in a interface between to use config join-group and create static igmp group address (config router multicast-flow)?

Because "Creating a static IGMP group entry ensures that FortiGate will preserve this IGMP group information for a given group and interface and will continue to deliver the multicast stream over the designated interface"

and join-group? can I use join-group to force remote pim enabled node to send me specific multicast group address  or what else? 

[dsrivastava]

https://community.fortinet.com/t5/FortiGate/Technical-Tip-Create-a-static-IGMP-group-entry/ta-p/1930...

Adding static-group for specific interface enables the Join request for a specified group, so always the stream will be sent towards this interface(then it will be forwarded towards the connected devices/receivers).

The Multicast-flow entries allows you a leverage of defining both group and source address ; however the 'config join-group' under PIM interfaces would allow you to set only group address.