Victron multiplus and smartsolar together

I have a question on how the multiplus and smartsolar systems integrate into a system.

1. How do each of these detect high/low voltage conditions in light of the fact that the other device might be putting a charge on the system? For instance if smartsolar is charging the battery how does multiplus know to not attempt to charge. Is this automatic or does it require manual intervention?
2. If using a bms (diy battery) that can control external devices like chargery or electrodacus, how to shutoff both of these devices in case of overcharge?
3. On undervoltage, again using a bms like chargery that controls the external equipment, what happens for the standard 12 volt system in an RV? From what I can see that is not routed through the multiplus so I guess it just stays live (but inverter shuts off), or do people normally install a relay on the 12v in addition to signally the multiplus?
4. I think the smartsolar needs a batterysense (sp?) device in order to learn the battery voltage and temperature,. Can one of these support both the smartsolar and multiplus, or is best practice to use 2?

I've looked around a bit but not seen schematics for this kind of setup that help understand, thanks in advance for any pointers.

Bob

If you have a Venus or CCGX you can set a total charge limit. If solar meets the limit, the MP will not charge. If solar cannot meet the limit it will supplement with shore power charging. I like to set the shore power charge voltage .1 or .2 volts lower than the solar. This will make sure solar is priority charge source.
They can also share the temperature from the MP temp sensor if Shared Temperature Sense is enabled in the Venus.
For shutoffs, you can use an external contactor controlled by a BMS, or you could get fancy and use the MP assistants, and utilize the I/O’s. It can be complicated to program the assistants, but it offers a ton of flexibility.

Okay, I see now the brains of the system is that Venus/ccgx. That answers a lot of questions. Thanks!