Hello Gianmaría,
I hope you are doing great,
The easiest thing would be that the other side (the branches), cofigure a Manual NAT NATing theirs subnets or hosts when they are destined to 192.168.1.0/24.
For example:
Remote site 1: TELTONIKA 3G Modem
IP: 192.168.6.10/?
nat (inside,outside) source static obj-192.168.6.0 obj-192.168.111.0 destination static obj-192.168.1.0 obj-192.168.1.0 no-proxy-arp route-lookup
Remote Site 2: TELTONIKA 3G Modem
LAN: 192.168.6.20/?
nat (inside,outside) source static obj-192.168.6.0 obj-192.168.112.0 destination static obj-192.168.1.0 obj-192.168.1.0
Remote Site 3: TELTONIKA 3G Modem
LAN: 192.168.6.30/?
nat (inside,outside) source static obj-192.168.6.0 obj-192.168.113.0 destination static obj-192.168.1.0 obj-192.168.1.0
On the ACL of the interesting traffic, now you are coming from the 192.168.1.0/24 to 192.168.11#.0/24 where # is the Remote site's number.
If you NAT this locally it would try to get the NATed IP on the other side and there isnt a NAT IP on the other side, so you would require the other side to do it, or you will need to create multiple contexts on the ASA and overcomplicate your scenario.
Keep me posted,
Please mark the answer as answered and rate the helpful answers!
Regards,
David Castro,