RSLogix 500 - Dynamic Destination IP (MSG)

Is it possible to configure the MSG block (RSLogix 500 / Micrologix 1400) to have a dynamic destination IP adress?

The MSG instruction in that PLC stores the IP address in a structured file type called Routing Information File. The IP data of an element of that file type appears in a data view window formatted in decimal octets, but "under the hood" I suspect it is still 32 bits. So, I just opened a file I have for one using Ethernet MSGs and tried to add a rung to MOV a L file (long integer, 32 bits) to a RI file element and it verifies.

This is definitely something that is outside the box, and would not be recommended but might be possible. I expect you will for sure have trouble if you were to write to that element when the message is in process or enabled and waiting.

So, it might be possible, and perhaps someone has already done it, but unless you have a really good reason, the safe bet is to stick with the brute force method of having unique MSG instructions for all your targets.