You probably want something like:
route-map neighbor1-out-map permit 10
match ip address ip-group1-1-list
set community 209:11111
set as-path prepend 64591 64591 64591 64591 64591
route-map neighbor1-out-map permit 20
match ip address ip-group1-2-list
set community 209:11122
set as-path prepend 64591 64591
route-map neighbor2-out-map permit 10
match ip address ip-group2-1-list
set community 209:22211
set as-path prepend 64591
route-map neighbor2-out-map permit 20
match ip address ip-group2-2-list
set community 209:22222
set as-path prepend 64591
So for your first neighbor you have the most restrictive group of IP subnets in ip-group1-1-list and you match that and apply communities and prepends as appropriate as permit statement 10. Your next group of IP subnets would be in permit statement 20. You could have a permit 30 with another group, and a permit 100 with no match but just set commands to do a default for everything not matched.
Duplicate the same for the second neighbor.
Apply the route-maps outbound as appropriate under the neighbors and clear ip bgp.
Route maps are processed in sequence order so the lowest sequence will be processed first, anything not matching sequence 10's match will be compared against sequence 20's match and so on. If no match then no community or prepends will be applied. Alternatively if you have a permit statement with just "set" statements then it will match everything not previously matched.
I typically use 10, 20, 30 to leave gaps so if you want to insert a policy between 10 and 20 you can just configure a permit 15 without having to re-type the whole thing.
