Multi select Lookup field Filter

You can add the filterConfig to the request. Something like this, first create the filter(s): 

const filter = new sdk.FilterGroup();
await filter.addSchemaColumnFilterWithParameter(sdk.ComparisonType.Equal, "UsrColumn", "Value");
 
// workaround for filters required in Creatio 8.1.0 and older
const newFilter = Object.assign({}, filter);
newFilter.items = filter.items;

Then add them in the request, something like this: 

entitySchemaType: "UsrMyLookupObject",
filtersConfig: {
	filterAttributes: [{
		name: "MyFilter",
		loadOnChange: false
	}],
	attributesConfig: {
		MyFilter: {
			value: newFilter
		}
	}
},

See additional examples here: https://community.creatio.com/questions/filter-crtopenlookuppagerequest

Ryan